Page 1
FINAL JEE –MAIN EXAMINATION – JANUARY, 2024
(Held On Saturday 27
th
January, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1.
?H ?I n 1 2 n
r r 1
C k 8 C
?M ?K ?]?M if and only if :
(1) 2 2 k 3 ?\?? (2) 2 3 k 3 2 ?\??
(3) 2 3 k 3 3 ?\?\ (4) 2 2 k 2 3 ?\?\
Ans. (1)
Sol.
n-1
C
r
= (k
2
– 8)
n
C
r+1
r 0
r 1 0, r 0
?? ?K ?? ??
n 1
2 r
n
r 1
C
k 8
C
?M ?K ?]?M
2
r 1
k 8
n
?K ?]?M
??
2
k 8 0 ?M?^
?H ?I ?H ?I k 2 2 k 2 2 0 ?M ?K ?^
?H ?I ?H ?I k , 2 2 2 2, ?? ?M ?? ?M ?? ?? …(I)
?| ?@ n r 1 ???K ,
r 1
1
n
?K ??
?? k
2
– 8 ???@ 1
k
2
– 9 ???@ 0
–3 ???@ k ?? 3 ….(II)
From equation (I) and (II) we get ?@ ?@ ?I ?H k 3, 2 2 2 2, 3
????
?? ?M ?M ??????
2. The distance, of the point (7, –2, 11) from the line
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?] along the line
x 5 y 1 z 5
2 3 6
?M ?M ?M ?]?]
?M , is :
(1) 12 (2) 14
(3) 18 (4) 21
Ans. (2)
Sol. B = (2 ?? +7, ?M 3 ?? – 2, 6 ?? + 11)
Point B lies on
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?]
2 7 6 3 2 4 6 11 8
1 0 3
?? ?K ?M ?M ?? ?M ?M ?? ?K ?M ?]?]
?M 3 ?? – 6 = 0
?? = –2
B ?? (3, 4, –1)
?H ?I ?H ?I ?H ?I 2 2 2
AB 7 3 4 2 11 1 ?] ?M ?K ?K ?K ?K
16 36 144 ?] ?K ?K
196 14 ?]?]
3. Let x = x(t) and y = y(t) be solutions of the
differential equations
dx
ax 0
dt
?K?] and
dy
by 0
dt
?K?] respectively, a, b ?? R. Given that
x(0) = 2; y(0) = 1 and 3y(1) = 2x(1), the value of t,
for which x(t) = y(t), is :
(1)
2
3
log 2 (2)
4
log 3
(3)
3
log 4
(4)
4
3
log 2
Ans. (4)
Page 2
FINAL JEE –MAIN EXAMINATION – JANUARY, 2024
(Held On Saturday 27
th
January, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1.
?H ?I n 1 2 n
r r 1
C k 8 C
?M ?K ?]?M if and only if :
(1) 2 2 k 3 ?\?? (2) 2 3 k 3 2 ?\??
(3) 2 3 k 3 3 ?\?\ (4) 2 2 k 2 3 ?\?\
Ans. (1)
Sol.
n-1
C
r
= (k
2
– 8)
n
C
r+1
r 0
r 1 0, r 0
?? ?K ?? ??
n 1
2 r
n
r 1
C
k 8
C
?M ?K ?]?M
2
r 1
k 8
n
?K ?]?M
??
2
k 8 0 ?M?^
?H ?I ?H ?I k 2 2 k 2 2 0 ?M ?K ?^
?H ?I ?H ?I k , 2 2 2 2, ?? ?M ?? ?M ?? ?? …(I)
?| ?@ n r 1 ???K ,
r 1
1
n
?K ??
?? k
2
– 8 ???@ 1
k
2
– 9 ???@ 0
–3 ???@ k ?? 3 ….(II)
From equation (I) and (II) we get ?@ ?@ ?I ?H k 3, 2 2 2 2, 3
????
?? ?M ?M ??????
2. The distance, of the point (7, –2, 11) from the line
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?] along the line
x 5 y 1 z 5
2 3 6
?M ?M ?M ?]?]
?M , is :
(1) 12 (2) 14
(3) 18 (4) 21
Ans. (2)
Sol. B = (2 ?? +7, ?M 3 ?? – 2, 6 ?? + 11)
Point B lies on
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?]
2 7 6 3 2 4 6 11 8
1 0 3
?? ?K ?M ?M ?? ?M ?M ?? ?K ?M ?]?]
?M 3 ?? – 6 = 0
?? = –2
B ?? (3, 4, –1)
?H ?I ?H ?I ?H ?I 2 2 2
AB 7 3 4 2 11 1 ?] ?M ?K ?K ?K ?K
16 36 144 ?] ?K ?K
196 14 ?]?]
3. Let x = x(t) and y = y(t) be solutions of the
differential equations
dx
ax 0
dt
?K?] and
dy
by 0
dt
?K?] respectively, a, b ?? R. Given that
x(0) = 2; y(0) = 1 and 3y(1) = 2x(1), the value of t,
for which x(t) = y(t), is :
(1)
2
3
log 2 (2)
4
log 3
(3)
3
log 4
(4)
4
3
log 2
Ans. (4)
Sol.
dx
ax 0
dt
?K?]
dx
adt
x
?]?M
dx
a dt
x
?]?M
????
ln | x | at c ?] ?M ?K
at t = 0, x = 2
ln 2 0 c ?]?K
ln x at ln 2 ?] ?M ?K
at
x
e
2
?M ?]
at
x 2e
?M ?] ….(i)
dy
by 0
dt
?K?]
dy
bdt
y
?]?M
ln | y | bt ?] ?M ?K ??
t = 0, y = 1
0 = 0 + ??
y = e
–bt
….(ii)
According to question
3y(1) = 2x(1)
3e
–b
= 2(2 e
–a
)
a b
4
e
3
?M ?]
For x(t) = y(t)
?? 2e
–at
= e
–bt
2 = e
(a – b)t
t
4
2
3
????
?] ????
????
4
3
log 2 t ?]
4. If (a, b) be the orthocentre of the triangle whose
vertices are (1, 2), (2, 3) and (3, 1), and
?H ?I b
2
1
a
I x sin 4x x dx ?]?M
?? ,
?H ?I b
2
2
a
I sin 4x x dx ?]?M
?? , then
1
2
I
36
I
is equal to :
(1) 72 (2) 88
(3) 80 (4) 66
Ans. (1)
Sol. Equation of CE
y – 1 = ?M (x – 3)
x + y = 4
orthocentre lies on the line x + y = 4
so, a + b = 4
?H ?I b
1
a
I x sin x(4 x) dx ?]?M
?? …(i)
Using king rule
?H ?I ?H ?I b
1
a
I 4 x sin x(4 x) dx ?] ?M ?M ?? …(ii)
(i) + (ii)
?H ?I b
1
a
2I 4sin x(4 x) dx ?]?M
??
2I
1
= 4I
2
I
1
= 2I
2
1
2
I
2
I
?]
1
2
36I
72
I
?]
5. If A denotes the sum of all the coefficients in the
expansion of (1 – 3x + 10x
2
)
n
and B denotes the
sum of all the coefficients in the expansion of
(1 + x
2
)
n
, then :
(1) A = B
3
(2) 3A = B
(3) B = A
3
(4) A = 3B
Ans. (1)
Sol. Sum of coefficients in the expansion of
(1 – 3x + 10x
2
)
n
= A
then A = (1 – 3 + 10)
n
?] 8
n
(put x = 1)
and sum of coefficients in the expansion of
(1 + x
2
)
n
= B
then B = (1 + 1)
n
= 2
n
A = B
3
Page 3
FINAL JEE –MAIN EXAMINATION – JANUARY, 2024
(Held On Saturday 27
th
January, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1.
?H ?I n 1 2 n
r r 1
C k 8 C
?M ?K ?]?M if and only if :
(1) 2 2 k 3 ?\?? (2) 2 3 k 3 2 ?\??
(3) 2 3 k 3 3 ?\?\ (4) 2 2 k 2 3 ?\?\
Ans. (1)
Sol.
n-1
C
r
= (k
2
– 8)
n
C
r+1
r 0
r 1 0, r 0
?? ?K ?? ??
n 1
2 r
n
r 1
C
k 8
C
?M ?K ?]?M
2
r 1
k 8
n
?K ?]?M
??
2
k 8 0 ?M?^
?H ?I ?H ?I k 2 2 k 2 2 0 ?M ?K ?^
?H ?I ?H ?I k , 2 2 2 2, ?? ?M ?? ?M ?? ?? …(I)
?| ?@ n r 1 ???K ,
r 1
1
n
?K ??
?? k
2
– 8 ???@ 1
k
2
– 9 ???@ 0
–3 ???@ k ?? 3 ….(II)
From equation (I) and (II) we get ?@ ?@ ?I ?H k 3, 2 2 2 2, 3
????
?? ?M ?M ??????
2. The distance, of the point (7, –2, 11) from the line
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?] along the line
x 5 y 1 z 5
2 3 6
?M ?M ?M ?]?]
?M , is :
(1) 12 (2) 14
(3) 18 (4) 21
Ans. (2)
Sol. B = (2 ?? +7, ?M 3 ?? – 2, 6 ?? + 11)
Point B lies on
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?]
2 7 6 3 2 4 6 11 8
1 0 3
?? ?K ?M ?M ?? ?M ?M ?? ?K ?M ?]?]
?M 3 ?? – 6 = 0
?? = –2
B ?? (3, 4, –1)
?H ?I ?H ?I ?H ?I 2 2 2
AB 7 3 4 2 11 1 ?] ?M ?K ?K ?K ?K
16 36 144 ?] ?K ?K
196 14 ?]?]
3. Let x = x(t) and y = y(t) be solutions of the
differential equations
dx
ax 0
dt
?K?] and
dy
by 0
dt
?K?] respectively, a, b ?? R. Given that
x(0) = 2; y(0) = 1 and 3y(1) = 2x(1), the value of t,
for which x(t) = y(t), is :
(1)
2
3
log 2 (2)
4
log 3
(3)
3
log 4
(4)
4
3
log 2
Ans. (4)
Sol.
dx
ax 0
dt
?K?]
dx
adt
x
?]?M
dx
a dt
x
?]?M
????
ln | x | at c ?] ?M ?K
at t = 0, x = 2
ln 2 0 c ?]?K
ln x at ln 2 ?] ?M ?K
at
x
e
2
?M ?]
at
x 2e
?M ?] ….(i)
dy
by 0
dt
?K?]
dy
bdt
y
?]?M
ln | y | bt ?] ?M ?K ??
t = 0, y = 1
0 = 0 + ??
y = e
–bt
….(ii)
According to question
3y(1) = 2x(1)
3e
–b
= 2(2 e
–a
)
a b
4
e
3
?M ?]
For x(t) = y(t)
?? 2e
–at
= e
–bt
2 = e
(a – b)t
t
4
2
3
????
?] ????
????
4
3
log 2 t ?]
4. If (a, b) be the orthocentre of the triangle whose
vertices are (1, 2), (2, 3) and (3, 1), and
?H ?I b
2
1
a
I x sin 4x x dx ?]?M
?? ,
?H ?I b
2
2
a
I sin 4x x dx ?]?M
?? , then
1
2
I
36
I
is equal to :
(1) 72 (2) 88
(3) 80 (4) 66
Ans. (1)
Sol. Equation of CE
y – 1 = ?M (x – 3)
x + y = 4
orthocentre lies on the line x + y = 4
so, a + b = 4
?H ?I b
1
a
I x sin x(4 x) dx ?]?M
?? …(i)
Using king rule
?H ?I ?H ?I b
1
a
I 4 x sin x(4 x) dx ?] ?M ?M ?? …(ii)
(i) + (ii)
?H ?I b
1
a
2I 4sin x(4 x) dx ?]?M
??
2I
1
= 4I
2
I
1
= 2I
2
1
2
I
2
I
?]
1
2
36I
72
I
?]
5. If A denotes the sum of all the coefficients in the
expansion of (1 – 3x + 10x
2
)
n
and B denotes the
sum of all the coefficients in the expansion of
(1 + x
2
)
n
, then :
(1) A = B
3
(2) 3A = B
(3) B = A
3
(4) A = 3B
Ans. (1)
Sol. Sum of coefficients in the expansion of
(1 – 3x + 10x
2
)
n
= A
then A = (1 – 3 + 10)
n
?] 8
n
(put x = 1)
and sum of coefficients in the expansion of
(1 + x
2
)
n
= B
then B = (1 + 1)
n
= 2
n
A = B
3
6. The number of common terms in the progressions
4, 9, 14, 19, ...... , up to 25
th
term and 3, 6, 9, 12,
......., up to 37
th
term is :
(1) 9 (2) 5
(3) 7 (4) 8
Ans. (3)
Sol. 4, 9, 14, 19, …., up to 25
th
term
T
25
= 4 + (25 – 1) 5 = 4 + 120 = 124
3, 6, 9, 12, …, up to 37
th
term
T
37
= 3 + (37 – 1)3 = 3 + 108 = 111
Common difference of I
st
series d
1
= 5
Common difference of II
nd
series d
2
= 3
First common term = 9, and
their common difference = 15 (LCM of d
1
and d
2
)
then common terms are
9, 24, 39, 54, 69, 84, 99
7. If the shortest distance of the parabola y
2
= 4x from
the centre of the circle x
2
+ y
2
– 4x – 16y + 64 = 0
is d, then d
2
is equal to :
(1) 16 (2) 24
(3) 20 (4) 36
Ans. (3)
Sol. Equation of normal to parabola
y = mx – 2m – m
3
this normal passing through center of circle (2, 8)
8 = 2m – 2m – m
3
m = –2
So point P on parabola ?? (am
2
, –2am) = (4, 4)
And C = (2, 8)
PC = 4 16 20 ?K?]
d
2
= 20
8. If the shortest distance between the lines
x 4 y 1 z
1 2 3
?M?K
?]?]
?M and
x y 1 z 2
2 4 5
?M ?? ?K ?M ?]?]
?M is
6
5
, then the sum of all possible values of ?? is :
(1) 5 (2) 8
(3) 7 (4) 10
Ans. (2)
Sol.
x 4 y 1 z
1 2 3
?M?K
?]?]
?M
x y 1 z 2
2 4 5
?M ?? ?K ?M ?]?]
?M
the shortest distance between the lines
?H ?I ?H ?I 1 2
1 2
a b d d
d d
?M ?? ?? ?] ??
4 0 2
1 2 3
2 4 5
ˆ
i j k
1 2 3
2 4 5
???M
?M ?M ?] ?M ?M
?H ?I ?H ?I ?H ?I 4 10 12 0 2 4 4
ˆ
2i 1j 0k
?? ?M ?M ?K ?M ?K ?M ?] ?M?K
?H ?I 2 4
6
5 5
???M
?]
3 = | ?? – 4|
?? – 4 = ±3
?? = 7, 1
Sum of all possible values of ?? is = 8
9. If
1
0
1
dx a b 2 c 3
3 x 1 x
?] ?K ?K ?K ?K ?K ?? , where
a, b, c are rational numbers, then 2a + 3b – 4c is
equal to :
(1) 4 (2) 10
(3) 7 (4) 8
Ans. (4)
Sol.
1
0
1
dx
3 x 1 x ?K ?K ?K ?? ?H ?I ?H ?I 1
0
3 x 1 x
dx
3 x 1 x
?K ?M ?K ?] ?K ?M ?K ??
?H ?I 1 1
0 0
1
3 x dx 1 x dx
2
????
?K ?M ?K ????
????
????
Page 4
FINAL JEE –MAIN EXAMINATION – JANUARY, 2024
(Held On Saturday 27
th
January, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1.
?H ?I n 1 2 n
r r 1
C k 8 C
?M ?K ?]?M if and only if :
(1) 2 2 k 3 ?\?? (2) 2 3 k 3 2 ?\??
(3) 2 3 k 3 3 ?\?\ (4) 2 2 k 2 3 ?\?\
Ans. (1)
Sol.
n-1
C
r
= (k
2
– 8)
n
C
r+1
r 0
r 1 0, r 0
?? ?K ?? ??
n 1
2 r
n
r 1
C
k 8
C
?M ?K ?]?M
2
r 1
k 8
n
?K ?]?M
??
2
k 8 0 ?M?^
?H ?I ?H ?I k 2 2 k 2 2 0 ?M ?K ?^
?H ?I ?H ?I k , 2 2 2 2, ?? ?M ?? ?M ?? ?? …(I)
?| ?@ n r 1 ???K ,
r 1
1
n
?K ??
?? k
2
– 8 ???@ 1
k
2
– 9 ???@ 0
–3 ???@ k ?? 3 ….(II)
From equation (I) and (II) we get ?@ ?@ ?I ?H k 3, 2 2 2 2, 3
????
?? ?M ?M ??????
2. The distance, of the point (7, –2, 11) from the line
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?] along the line
x 5 y 1 z 5
2 3 6
?M ?M ?M ?]?]
?M , is :
(1) 12 (2) 14
(3) 18 (4) 21
Ans. (2)
Sol. B = (2 ?? +7, ?M 3 ?? – 2, 6 ?? + 11)
Point B lies on
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?]
2 7 6 3 2 4 6 11 8
1 0 3
?? ?K ?M ?M ?? ?M ?M ?? ?K ?M ?]?]
?M 3 ?? – 6 = 0
?? = –2
B ?? (3, 4, –1)
?H ?I ?H ?I ?H ?I 2 2 2
AB 7 3 4 2 11 1 ?] ?M ?K ?K ?K ?K
16 36 144 ?] ?K ?K
196 14 ?]?]
3. Let x = x(t) and y = y(t) be solutions of the
differential equations
dx
ax 0
dt
?K?] and
dy
by 0
dt
?K?] respectively, a, b ?? R. Given that
x(0) = 2; y(0) = 1 and 3y(1) = 2x(1), the value of t,
for which x(t) = y(t), is :
(1)
2
3
log 2 (2)
4
log 3
(3)
3
log 4
(4)
4
3
log 2
Ans. (4)
Sol.
dx
ax 0
dt
?K?]
dx
adt
x
?]?M
dx
a dt
x
?]?M
????
ln | x | at c ?] ?M ?K
at t = 0, x = 2
ln 2 0 c ?]?K
ln x at ln 2 ?] ?M ?K
at
x
e
2
?M ?]
at
x 2e
?M ?] ….(i)
dy
by 0
dt
?K?]
dy
bdt
y
?]?M
ln | y | bt ?] ?M ?K ??
t = 0, y = 1
0 = 0 + ??
y = e
–bt
….(ii)
According to question
3y(1) = 2x(1)
3e
–b
= 2(2 e
–a
)
a b
4
e
3
?M ?]
For x(t) = y(t)
?? 2e
–at
= e
–bt
2 = e
(a – b)t
t
4
2
3
????
?] ????
????
4
3
log 2 t ?]
4. If (a, b) be the orthocentre of the triangle whose
vertices are (1, 2), (2, 3) and (3, 1), and
?H ?I b
2
1
a
I x sin 4x x dx ?]?M
?? ,
?H ?I b
2
2
a
I sin 4x x dx ?]?M
?? , then
1
2
I
36
I
is equal to :
(1) 72 (2) 88
(3) 80 (4) 66
Ans. (1)
Sol. Equation of CE
y – 1 = ?M (x – 3)
x + y = 4
orthocentre lies on the line x + y = 4
so, a + b = 4
?H ?I b
1
a
I x sin x(4 x) dx ?]?M
?? …(i)
Using king rule
?H ?I ?H ?I b
1
a
I 4 x sin x(4 x) dx ?] ?M ?M ?? …(ii)
(i) + (ii)
?H ?I b
1
a
2I 4sin x(4 x) dx ?]?M
??
2I
1
= 4I
2
I
1
= 2I
2
1
2
I
2
I
?]
1
2
36I
72
I
?]
5. If A denotes the sum of all the coefficients in the
expansion of (1 – 3x + 10x
2
)
n
and B denotes the
sum of all the coefficients in the expansion of
(1 + x
2
)
n
, then :
(1) A = B
3
(2) 3A = B
(3) B = A
3
(4) A = 3B
Ans. (1)
Sol. Sum of coefficients in the expansion of
(1 – 3x + 10x
2
)
n
= A
then A = (1 – 3 + 10)
n
?] 8
n
(put x = 1)
and sum of coefficients in the expansion of
(1 + x
2
)
n
= B
then B = (1 + 1)
n
= 2
n
A = B
3
6. The number of common terms in the progressions
4, 9, 14, 19, ...... , up to 25
th
term and 3, 6, 9, 12,
......., up to 37
th
term is :
(1) 9 (2) 5
(3) 7 (4) 8
Ans. (3)
Sol. 4, 9, 14, 19, …., up to 25
th
term
T
25
= 4 + (25 – 1) 5 = 4 + 120 = 124
3, 6, 9, 12, …, up to 37
th
term
T
37
= 3 + (37 – 1)3 = 3 + 108 = 111
Common difference of I
st
series d
1
= 5
Common difference of II
nd
series d
2
= 3
First common term = 9, and
their common difference = 15 (LCM of d
1
and d
2
)
then common terms are
9, 24, 39, 54, 69, 84, 99
7. If the shortest distance of the parabola y
2
= 4x from
the centre of the circle x
2
+ y
2
– 4x – 16y + 64 = 0
is d, then d
2
is equal to :
(1) 16 (2) 24
(3) 20 (4) 36
Ans. (3)
Sol. Equation of normal to parabola
y = mx – 2m – m
3
this normal passing through center of circle (2, 8)
8 = 2m – 2m – m
3
m = –2
So point P on parabola ?? (am
2
, –2am) = (4, 4)
And C = (2, 8)
PC = 4 16 20 ?K?]
d
2
= 20
8. If the shortest distance between the lines
x 4 y 1 z
1 2 3
?M?K
?]?]
?M and
x y 1 z 2
2 4 5
?M ?? ?K ?M ?]?]
?M is
6
5
, then the sum of all possible values of ?? is :
(1) 5 (2) 8
(3) 7 (4) 10
Ans. (2)
Sol.
x 4 y 1 z
1 2 3
?M?K
?]?]
?M
x y 1 z 2
2 4 5
?M ?? ?K ?M ?]?]
?M
the shortest distance between the lines
?H ?I ?H ?I 1 2
1 2
a b d d
d d
?M ?? ?? ?] ??
4 0 2
1 2 3
2 4 5
ˆ
i j k
1 2 3
2 4 5
???M
?M ?M ?] ?M ?M
?H ?I ?H ?I ?H ?I 4 10 12 0 2 4 4
ˆ
2i 1j 0k
?? ?M ?M ?K ?M ?K ?M ?] ?M?K
?H ?I 2 4
6
5 5
???M
?]
3 = | ?? – 4|
?? – 4 = ±3
?? = 7, 1
Sum of all possible values of ?? is = 8
9. If
1
0
1
dx a b 2 c 3
3 x 1 x
?] ?K ?K ?K ?K ?K ?? , where
a, b, c are rational numbers, then 2a + 3b – 4c is
equal to :
(1) 4 (2) 10
(3) 7 (4) 8
Ans. (4)
Sol.
1
0
1
dx
3 x 1 x ?K ?K ?K ?? ?H ?I ?H ?I 1
0
3 x 1 x
dx
3 x 1 x
?K ?M ?K ?] ?K ?M ?K ??
?H ?I 1 1
0 0
1
3 x dx 1 x dx
2
????
?K ?M ?K ????
????
????
?H ?I ?H ?I 1
3 3
2 2
0
3 x 2 1 x
1
2
2 3 3
????
?K?K
????
?M ????
????
????
?H ?I 3
2
1 2 2
8 3 3 2 1
2 3 3
???? ????
?M ?M ?M ???? ????
????
???? ????
1
8 3 3 2 2 1
3
????
?M ?M ?K ????
2
3 3 2 a b 2 c 3
3
?] ?M ?M ?] ?K ?K
2
a 3, b , c 1
3
?] ?] ?M ?] ?M
2a + 3b – 4c = 6 – 2 + 4 = 8
10. Let S = {l, 2, 3, ... , 10}. Suppose M is the set of all
the subsets of S, then the relation
R = {(A, B): A ?? B ?? ?? ; A, B ?? M} is :
(1) symmetric and reflexive only
(2) reflexive only
(3) symmetric and transitive only
(4) symmetric only
Ans. (4)
Sol. Let S = {1, 2, 3, …, 10}
R = {(A, B): A ?? B ?? ?? ; A, B ?? M}
For Reflexive,
M is subset of ‘S’
So ?? ?@?? M
for ?? ?? ?? = ??
?? but relation is A ?? B ?? ??
So it is not reflexive.
For symmetric,
ARB A ?? B ?? ?? ,
?? BRA ?? B ?? A ?? ?? ,
So it is symmetric.
For transitive,
If A = {(1, 2), (2, 3)}
B = {(2, 3), (3, 4)}
C = {(3, 4), (5, 6)}
ARB & BRC but A does not relate to C
So it not transitive
11. If S = {z ?? C : |z – i| = |z + i| = |z–1|}, then, n(S) is:
(1) 1 (2) 0
(3) 3 (4) 2
Ans. (1)
Sol. |z – i| = |z + i| = |z – 1|
ABC is a triangle. Hence its circum-centre will be
the only point whose distance from A, B, C will be
same.
So n(S) = 1
12. Four distinct points (2k, 3k), (1, 0), (0, 1) and
(0, 0) lie on a circle for k equal to :
(1)
2
13
(2)
3
13
(3)
5
13
(4)
1
13
Ans. (3)
Sol. (2k, 3k) will lie on circle whose diameter is AB.
(x – 1) (x) + (y – 1) (y) = 0
x
2
+ y
2
– x – y = 0 …(i)
Satisfy (2k, 3k) in (i)
(2k)
2
+ (3k)
2
– 2k – 3k = 0
13k
2
– 5k = 0
k = 0,
5
k
13
?]
hence
5
k
13
?]
Page 5
FINAL JEE –MAIN EXAMINATION – JANUARY, 2024
(Held On Saturday 27
th
January, 2024) TIME : 9 : 00 AM to 12 : 00 NOON
MATHEMATICS TEST PAPER WITH SOLUTION
SECTION-A
1.
?H ?I n 1 2 n
r r 1
C k 8 C
?M ?K ?]?M if and only if :
(1) 2 2 k 3 ?\?? (2) 2 3 k 3 2 ?\??
(3) 2 3 k 3 3 ?\?\ (4) 2 2 k 2 3 ?\?\
Ans. (1)
Sol.
n-1
C
r
= (k
2
– 8)
n
C
r+1
r 0
r 1 0, r 0
?? ?K ?? ??
n 1
2 r
n
r 1
C
k 8
C
?M ?K ?]?M
2
r 1
k 8
n
?K ?]?M
??
2
k 8 0 ?M?^
?H ?I ?H ?I k 2 2 k 2 2 0 ?M ?K ?^
?H ?I ?H ?I k , 2 2 2 2, ?? ?M ?? ?M ?? ?? …(I)
?| ?@ n r 1 ???K ,
r 1
1
n
?K ??
?? k
2
– 8 ???@ 1
k
2
– 9 ???@ 0
–3 ???@ k ?? 3 ….(II)
From equation (I) and (II) we get ?@ ?@ ?I ?H k 3, 2 2 2 2, 3
????
?? ?M ?M ??????
2. The distance, of the point (7, –2, 11) from the line
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?] along the line
x 5 y 1 z 5
2 3 6
?M ?M ?M ?]?]
?M , is :
(1) 12 (2) 14
(3) 18 (4) 21
Ans. (2)
Sol. B = (2 ?? +7, ?M 3 ?? – 2, 6 ?? + 11)
Point B lies on
x 6 y 4 z 8
1 0 3
?M ?M ?M ?]?]
2 7 6 3 2 4 6 11 8
1 0 3
?? ?K ?M ?M ?? ?M ?M ?? ?K ?M ?]?]
?M 3 ?? – 6 = 0
?? = –2
B ?? (3, 4, –1)
?H ?I ?H ?I ?H ?I 2 2 2
AB 7 3 4 2 11 1 ?] ?M ?K ?K ?K ?K
16 36 144 ?] ?K ?K
196 14 ?]?]
3. Let x = x(t) and y = y(t) be solutions of the
differential equations
dx
ax 0
dt
?K?] and
dy
by 0
dt
?K?] respectively, a, b ?? R. Given that
x(0) = 2; y(0) = 1 and 3y(1) = 2x(1), the value of t,
for which x(t) = y(t), is :
(1)
2
3
log 2 (2)
4
log 3
(3)
3
log 4
(4)
4
3
log 2
Ans. (4)
Sol.
dx
ax 0
dt
?K?]
dx
adt
x
?]?M
dx
a dt
x
?]?M
????
ln | x | at c ?] ?M ?K
at t = 0, x = 2
ln 2 0 c ?]?K
ln x at ln 2 ?] ?M ?K
at
x
e
2
?M ?]
at
x 2e
?M ?] ….(i)
dy
by 0
dt
?K?]
dy
bdt
y
?]?M
ln | y | bt ?] ?M ?K ??
t = 0, y = 1
0 = 0 + ??
y = e
–bt
….(ii)
According to question
3y(1) = 2x(1)
3e
–b
= 2(2 e
–a
)
a b
4
e
3
?M ?]
For x(t) = y(t)
?? 2e
–at
= e
–bt
2 = e
(a – b)t
t
4
2
3
????
?] ????
????
4
3
log 2 t ?]
4. If (a, b) be the orthocentre of the triangle whose
vertices are (1, 2), (2, 3) and (3, 1), and
?H ?I b
2
1
a
I x sin 4x x dx ?]?M
?? ,
?H ?I b
2
2
a
I sin 4x x dx ?]?M
?? , then
1
2
I
36
I
is equal to :
(1) 72 (2) 88
(3) 80 (4) 66
Ans. (1)
Sol. Equation of CE
y – 1 = ?M (x – 3)
x + y = 4
orthocentre lies on the line x + y = 4
so, a + b = 4
?H ?I b
1
a
I x sin x(4 x) dx ?]?M
?? …(i)
Using king rule
?H ?I ?H ?I b
1
a
I 4 x sin x(4 x) dx ?] ?M ?M ?? …(ii)
(i) + (ii)
?H ?I b
1
a
2I 4sin x(4 x) dx ?]?M
??
2I
1
= 4I
2
I
1
= 2I
2
1
2
I
2
I
?]
1
2
36I
72
I
?]
5. If A denotes the sum of all the coefficients in the
expansion of (1 – 3x + 10x
2
)
n
and B denotes the
sum of all the coefficients in the expansion of
(1 + x
2
)
n
, then :
(1) A = B
3
(2) 3A = B
(3) B = A
3
(4) A = 3B
Ans. (1)
Sol. Sum of coefficients in the expansion of
(1 – 3x + 10x
2
)
n
= A
then A = (1 – 3 + 10)
n
?] 8
n
(put x = 1)
and sum of coefficients in the expansion of
(1 + x
2
)
n
= B
then B = (1 + 1)
n
= 2
n
A = B
3
6. The number of common terms in the progressions
4, 9, 14, 19, ...... , up to 25
th
term and 3, 6, 9, 12,
......., up to 37
th
term is :
(1) 9 (2) 5
(3) 7 (4) 8
Ans. (3)
Sol. 4, 9, 14, 19, …., up to 25
th
term
T
25
= 4 + (25 – 1) 5 = 4 + 120 = 124
3, 6, 9, 12, …, up to 37
th
term
T
37
= 3 + (37 – 1)3 = 3 + 108 = 111
Common difference of I
st
series d
1
= 5
Common difference of II
nd
series d
2
= 3
First common term = 9, and
their common difference = 15 (LCM of d
1
and d
2
)
then common terms are
9, 24, 39, 54, 69, 84, 99
7. If the shortest distance of the parabola y
2
= 4x from
the centre of the circle x
2
+ y
2
– 4x – 16y + 64 = 0
is d, then d
2
is equal to :
(1) 16 (2) 24
(3) 20 (4) 36
Ans. (3)
Sol. Equation of normal to parabola
y = mx – 2m – m
3
this normal passing through center of circle (2, 8)
8 = 2m – 2m – m
3
m = –2
So point P on parabola ?? (am
2
, –2am) = (4, 4)
And C = (2, 8)
PC = 4 16 20 ?K?]
d
2
= 20
8. If the shortest distance between the lines
x 4 y 1 z
1 2 3
?M?K
?]?]
?M and
x y 1 z 2
2 4 5
?M ?? ?K ?M ?]?]
?M is
6
5
, then the sum of all possible values of ?? is :
(1) 5 (2) 8
(3) 7 (4) 10
Ans. (2)
Sol.
x 4 y 1 z
1 2 3
?M?K
?]?]
?M
x y 1 z 2
2 4 5
?M ?? ?K ?M ?]?]
?M
the shortest distance between the lines
?H ?I ?H ?I 1 2
1 2
a b d d
d d
?M ?? ?? ?] ??
4 0 2
1 2 3
2 4 5
ˆ
i j k
1 2 3
2 4 5
???M
?M ?M ?] ?M ?M
?H ?I ?H ?I ?H ?I 4 10 12 0 2 4 4
ˆ
2i 1j 0k
?? ?M ?M ?K ?M ?K ?M ?] ?M?K
?H ?I 2 4
6
5 5
???M
?]
3 = | ?? – 4|
?? – 4 = ±3
?? = 7, 1
Sum of all possible values of ?? is = 8
9. If
1
0
1
dx a b 2 c 3
3 x 1 x
?] ?K ?K ?K ?K ?K ?? , where
a, b, c are rational numbers, then 2a + 3b – 4c is
equal to :
(1) 4 (2) 10
(3) 7 (4) 8
Ans. (4)
Sol.
1
0
1
dx
3 x 1 x ?K ?K ?K ?? ?H ?I ?H ?I 1
0
3 x 1 x
dx
3 x 1 x
?K ?M ?K ?] ?K ?M ?K ??
?H ?I 1 1
0 0
1
3 x dx 1 x dx
2
????
?K ?M ?K ????
????
????
?H ?I ?H ?I 1
3 3
2 2
0
3 x 2 1 x
1
2
2 3 3
????
?K?K
????
?M ????
????
????
?H ?I 3
2
1 2 2
8 3 3 2 1
2 3 3
???? ????
?M ?M ?M ???? ????
????
???? ????
1
8 3 3 2 2 1
3
????
?M ?M ?K ????
2
3 3 2 a b 2 c 3
3
?] ?M ?M ?] ?K ?K
2
a 3, b , c 1
3
?] ?] ?M ?] ?M
2a + 3b – 4c = 6 – 2 + 4 = 8
10. Let S = {l, 2, 3, ... , 10}. Suppose M is the set of all
the subsets of S, then the relation
R = {(A, B): A ?? B ?? ?? ; A, B ?? M} is :
(1) symmetric and reflexive only
(2) reflexive only
(3) symmetric and transitive only
(4) symmetric only
Ans. (4)
Sol. Let S = {1, 2, 3, …, 10}
R = {(A, B): A ?? B ?? ?? ; A, B ?? M}
For Reflexive,
M is subset of ‘S’
So ?? ?@?? M
for ?? ?? ?? = ??
?? but relation is A ?? B ?? ??
So it is not reflexive.
For symmetric,
ARB A ?? B ?? ?? ,
?? BRA ?? B ?? A ?? ?? ,
So it is symmetric.
For transitive,
If A = {(1, 2), (2, 3)}
B = {(2, 3), (3, 4)}
C = {(3, 4), (5, 6)}
ARB & BRC but A does not relate to C
So it not transitive
11. If S = {z ?? C : |z – i| = |z + i| = |z–1|}, then, n(S) is:
(1) 1 (2) 0
(3) 3 (4) 2
Ans. (1)
Sol. |z – i| = |z + i| = |z – 1|
ABC is a triangle. Hence its circum-centre will be
the only point whose distance from A, B, C will be
same.
So n(S) = 1
12. Four distinct points (2k, 3k), (1, 0), (0, 1) and
(0, 0) lie on a circle for k equal to :
(1)
2
13
(2)
3
13
(3)
5
13
(4)
1
13
Ans. (3)
Sol. (2k, 3k) will lie on circle whose diameter is AB.
(x – 1) (x) + (y – 1) (y) = 0
x
2
+ y
2
– x – y = 0 …(i)
Satisfy (2k, 3k) in (i)
(2k)
2
+ (3k)
2
– 2k – 3k = 0
13k
2
– 5k = 0
k = 0,
5
k
13
?]
hence
5
k
13
?]
13. Consider the function.
?H ?I ?H ?I 2
2
sin x 3
x [x]
a 7x 12 x
, x 3
b x 7x 12
f (x) 2 , x 3
b , x 3
?M ?M ?? ?M?M
?? ?\ ?M?K
?? ?? ???]?^
?? ?? ?] ?? ?? ?? ??
Where [x] denotes the greatest integer less than or
equal to x. If S denotes the set of all ordered pairs
(a, b) such that f(x) is continuous at x = 3, then the
number of elements in S is :
(1) 2 (2) Infinitely many
(3) 4 (4) 1
Ans. (4)
Sol.
?H ?I ?H ?I 2
2
7x 12 x
a
f 3
b x 7x 12
?M ?M?M
?] ?M?K
(for f(x) to be cont.)
?? f(3
–
) =
?H ?I ?H ?I ?H ?I ?H ?I x 3 x 4
a
;x 3
b x 3 x 4
?M?M
?M ?\ ?M?M
??
a
b
?M
Hence
?H ?I a
f 3
b
?M ?M ?]
Then
?H ?I ?H ?I x 3
sin x 3
lim
x 3
f 3 2 2
?K ?? ?M ????
????
????
?M ?K ????
?]?] and
f(3) = b.
Hence f(3) = f(3
+
) = f(3
–
)
?? b = 2 =
a
b
?M
b = 2, a = –4
Hence only 1 ordered pair (–4, 2).
14. Let a
1
, a
2
, ….. a
10
be 10 observations such that
10
k
k 1
a 50
?] ?] ?? and
k j
k j
a a 1100
?B?\
???]
?? . Then the
standard deviation of a
1
, a
2
, .., a
10
is equal to :
(1) 5 (2) 5
(3) 10 (4) 115
Ans. (2)
Sol.
10
k
k 1
a 50
?] ?] ??
a
1
+ a
2
+ … + a
10
= 50 ….(i)
k j
k j
a a 1100
?B?\
?] ?? ....(ii)
If a
1
+ a
2
+ … + a
10
= 50.
(a
1
+ a
2
+ … + a
10
)
2
= 2500
?? 10
2
i k j
i 1 k j
a 2 a a 2500
?]?\
?K?]
????
?? ?H ?I 10
2
i
i 1
a 2500 2 1100
?] ?]?M
??
10
2
i
i 1
a 300
?] ?] ?? , Standard deviation ‘ ?? ’
2
2
2
i i
a a
300 50
10 10 10 10
????
????
????
???? ?] ?M ?] ?M ????
???? ????
????
????
????
30 25 5 ?] ?M ?]
15. The length of the chord of the ellipse
2 2
x y
1
25 16
?K?] ,
whose mid point is
2
1,
5
????
????
????
, is equal to :
(1)
1691
5
(2)
2009
5
(3)
1741
5
(4)
1541
5
Ans. (1)
Sol. Equation of chord with given middle point.
T = S
1
x y 1 1
25 40 25 100
?K ?] ?K
8x 5y 8 2
200 200
?K?K
?]
10 8x
y
5
?M ?] …(i)
Read More