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NCERT Solutions, Exercise 5.2, Arithmetic Progression, Class 10 (Mathematics) PDF Download

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Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
1 
Exercise 5.2 
Question 1:  
Fill in the blanks in the following table, given that a is the first term, d 
the common difference and an the n
th
 term of the A.P.  
  a d n an 
I 7 3 8 …... 
II - 18 ….. 10 0 
III ….. - 3 18 - 5 
IV - 18.9 2.5 ….. 3.6 
V 3.5 0 105 ….. 
 
Answer 1:  
I. a = 7, d = 3, n = 8, an = ?  
We know that,  
For an A.P. an = a + (n - 1) d  
= 7 + (8 - 1) 3  
= 7 + (7) 3  
= 7 + 21 = 28  
Hence, an = 28  
II. Given that a = -18, n = 10, an = 0, d = ?  
We know that,  
an = a + (n - 1) d  
0 = - 18 + (10 - 1) d  
18 = 9d  
Page 2


Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
1 
Exercise 5.2 
Question 1:  
Fill in the blanks in the following table, given that a is the first term, d 
the common difference and an the n
th
 term of the A.P.  
  a d n an 
I 7 3 8 …... 
II - 18 ….. 10 0 
III ….. - 3 18 - 5 
IV - 18.9 2.5 ….. 3.6 
V 3.5 0 105 ….. 
 
Answer 1:  
I. a = 7, d = 3, n = 8, an = ?  
We know that,  
For an A.P. an = a + (n - 1) d  
= 7 + (8 - 1) 3  
= 7 + (7) 3  
= 7 + 21 = 28  
Hence, an = 28  
II. Given that a = -18, n = 10, an = 0, d = ?  
We know that,  
an = a + (n - 1) d  
0 = - 18 + (10 - 1) d  
18 = 9d  
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
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2 
  
Hence, common difference, d = 2  
 
III. Given that d = -3, n = 18, an = -5  
 
We know that, an = a + (n - 1) d  
 
-5 = a + (18 - 1) (-3)  
-5 = a + (17) (-3)  
-5 = a - 51  
a = 51 - 5 = 46  
Hence, a = 46  
 
IV. a = -18.9, d = 2.5, an = 3.6, n = ?  
We know that, an = a + (n - 1) d  
3.6 = - 18.9 + (n - 1) 2.5  
3.6 + 18.9 = (n - 1) 2.5  
22.5 = (n - 1) 2.5  
  
Hence, n = 10  
 
V. a = 3.5, d = 0, n = 105, an = ?  
We know that, an = a + (n - 1) d  
an = 3.5 + (105 - 1) 0  
an = 3.5 + 104 × 0  
an = 3.5  
Hence, an = 3.5  
 
 
Page 3


Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
1 
Exercise 5.2 
Question 1:  
Fill in the blanks in the following table, given that a is the first term, d 
the common difference and an the n
th
 term of the A.P.  
  a d n an 
I 7 3 8 …... 
II - 18 ….. 10 0 
III ….. - 3 18 - 5 
IV - 18.9 2.5 ….. 3.6 
V 3.5 0 105 ….. 
 
Answer 1:  
I. a = 7, d = 3, n = 8, an = ?  
We know that,  
For an A.P. an = a + (n - 1) d  
= 7 + (8 - 1) 3  
= 7 + (7) 3  
= 7 + 21 = 28  
Hence, an = 28  
II. Given that a = -18, n = 10, an = 0, d = ?  
We know that,  
an = a + (n - 1) d  
0 = - 18 + (10 - 1) d  
18 = 9d  
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
2 
  
Hence, common difference, d = 2  
 
III. Given that d = -3, n = 18, an = -5  
 
We know that, an = a + (n - 1) d  
 
-5 = a + (18 - 1) (-3)  
-5 = a + (17) (-3)  
-5 = a - 51  
a = 51 - 5 = 46  
Hence, a = 46  
 
IV. a = -18.9, d = 2.5, an = 3.6, n = ?  
We know that, an = a + (n - 1) d  
3.6 = - 18.9 + (n - 1) 2.5  
3.6 + 18.9 = (n - 1) 2.5  
22.5 = (n - 1) 2.5  
  
Hence, n = 10  
 
V. a = 3.5, d = 0, n = 105, an = ?  
We know that, an = a + (n - 1) d  
an = 3.5 + (105 - 1) 0  
an = 3.5 + 104 × 0  
an = 3.5  
Hence, an = 3.5  
 
 
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
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3 
 
Question 2:  
Choose the correct choice in the following and justify  
(i). 30
th
 term of the A.P: 10, 7, 4, …, is  
 
       (A). 97  (B). 77  (C). - 77  (D). - 87  
(ii).  11
th
 term of the A.P.                 is  
        (A). 28  (B). 22  (C). - 38  (D).  
 
Answer 2:  
(i) Given that  
A.P. 10, 7, 4, …  
 
First term, a = 10  
 
Common difference, d = a2 - a1 = 7 - 10 = -3  
We know that, an = a + (n - 1) d  
 
a30 = 10 + (30 - 1) (-3)  
a30 = 10 + (29) (-3)  
a30 = 10 - 87 = -77  
 
Hence, the correct answer is C.  
 
 
(ii) Given that, A.P.   
First term a = -3  
Common difference, d = a2 - a1  
Page 4


Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
1 
Exercise 5.2 
Question 1:  
Fill in the blanks in the following table, given that a is the first term, d 
the common difference and an the n
th
 term of the A.P.  
  a d n an 
I 7 3 8 …... 
II - 18 ….. 10 0 
III ….. - 3 18 - 5 
IV - 18.9 2.5 ….. 3.6 
V 3.5 0 105 ….. 
 
Answer 1:  
I. a = 7, d = 3, n = 8, an = ?  
We know that,  
For an A.P. an = a + (n - 1) d  
= 7 + (8 - 1) 3  
= 7 + (7) 3  
= 7 + 21 = 28  
Hence, an = 28  
II. Given that a = -18, n = 10, an = 0, d = ?  
We know that,  
an = a + (n - 1) d  
0 = - 18 + (10 - 1) d  
18 = 9d  
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
2 
  
Hence, common difference, d = 2  
 
III. Given that d = -3, n = 18, an = -5  
 
We know that, an = a + (n - 1) d  
 
-5 = a + (18 - 1) (-3)  
-5 = a + (17) (-3)  
-5 = a - 51  
a = 51 - 5 = 46  
Hence, a = 46  
 
IV. a = -18.9, d = 2.5, an = 3.6, n = ?  
We know that, an = a + (n - 1) d  
3.6 = - 18.9 + (n - 1) 2.5  
3.6 + 18.9 = (n - 1) 2.5  
22.5 = (n - 1) 2.5  
  
Hence, n = 10  
 
V. a = 3.5, d = 0, n = 105, an = ?  
We know that, an = a + (n - 1) d  
an = 3.5 + (105 - 1) 0  
an = 3.5 + 104 × 0  
an = 3.5  
Hence, an = 3.5  
 
 
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
3 
 
Question 2:  
Choose the correct choice in the following and justify  
(i). 30
th
 term of the A.P: 10, 7, 4, …, is  
 
       (A). 97  (B). 77  (C). - 77  (D). - 87  
(ii).  11
th
 term of the A.P.                 is  
        (A). 28  (B). 22  (C). - 38  (D).  
 
Answer 2:  
(i) Given that  
A.P. 10, 7, 4, …  
 
First term, a = 10  
 
Common difference, d = a2 - a1 = 7 - 10 = -3  
We know that, an = a + (n - 1) d  
 
a30 = 10 + (30 - 1) (-3)  
a30 = 10 + (29) (-3)  
a30 = 10 - 87 = -77  
 
Hence, the correct answer is C.  
 
 
(ii) Given that, A.P.   
First term a = -3  
Common difference, d = a2 - a1  
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
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4 
  
We know that,  
  
Hence, the answer is B.  
 
Question 3:  
In the following APs find the missing term in the boxes  
 
(i)   
(ii)   
(iii)           
(iv)                  
    (v) 
 
Answer 3:  
(i)    
For this A.P., a = 2 and a3 = 26  
Page 5


Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
1 
Exercise 5.2 
Question 1:  
Fill in the blanks in the following table, given that a is the first term, d 
the common difference and an the n
th
 term of the A.P.  
  a d n an 
I 7 3 8 …... 
II - 18 ….. 10 0 
III ….. - 3 18 - 5 
IV - 18.9 2.5 ….. 3.6 
V 3.5 0 105 ….. 
 
Answer 1:  
I. a = 7, d = 3, n = 8, an = ?  
We know that,  
For an A.P. an = a + (n - 1) d  
= 7 + (8 - 1) 3  
= 7 + (7) 3  
= 7 + 21 = 28  
Hence, an = 28  
II. Given that a = -18, n = 10, an = 0, d = ?  
We know that,  
an = a + (n - 1) d  
0 = - 18 + (10 - 1) d  
18 = 9d  
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
2 
  
Hence, common difference, d = 2  
 
III. Given that d = -3, n = 18, an = -5  
 
We know that, an = a + (n - 1) d  
 
-5 = a + (18 - 1) (-3)  
-5 = a + (17) (-3)  
-5 = a - 51  
a = 51 - 5 = 46  
Hence, a = 46  
 
IV. a = -18.9, d = 2.5, an = 3.6, n = ?  
We know that, an = a + (n - 1) d  
3.6 = - 18.9 + (n - 1) 2.5  
3.6 + 18.9 = (n - 1) 2.5  
22.5 = (n - 1) 2.5  
  
Hence, n = 10  
 
V. a = 3.5, d = 0, n = 105, an = ?  
We know that, an = a + (n - 1) d  
an = 3.5 + (105 - 1) 0  
an = 3.5 + 104 × 0  
an = 3.5  
Hence, an = 3.5  
 
 
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
www.tiwariacademy.com 
3 
 
Question 2:  
Choose the correct choice in the following and justify  
(i). 30
th
 term of the A.P: 10, 7, 4, …, is  
 
       (A). 97  (B). 77  (C). - 77  (D). - 87  
(ii).  11
th
 term of the A.P.                 is  
        (A). 28  (B). 22  (C). - 38  (D).  
 
Answer 2:  
(i) Given that  
A.P. 10, 7, 4, …  
 
First term, a = 10  
 
Common difference, d = a2 - a1 = 7 - 10 = -3  
We know that, an = a + (n - 1) d  
 
a30 = 10 + (30 - 1) (-3)  
a30 = 10 + (29) (-3)  
a30 = 10 - 87 = -77  
 
Hence, the correct answer is C.  
 
 
(ii) Given that, A.P.   
First term a = -3  
Common difference, d = a2 - a1  
Mathematics 
(www.tiwariacademy.com) 
(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
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4 
  
We know that,  
  
Hence, the answer is B.  
 
Question 3:  
In the following APs find the missing term in the boxes  
 
(i)   
(ii)   
(iii)           
(iv)                  
    (v) 
 
Answer 3:  
(i)    
For this A.P., a = 2 and a3 = 26  
Mathematics 
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(Chapter – 5) (Arithmetic Progressions)  
(Class – X) 
  
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5 
We know that, an = a + (n - 1) d  
a3 = 2 + (3 - 1) d  
26 = 2 + 2d  
24 = 2d d = 12  
 
a2 = 2 + (2 - 1) 12  
= 14  
Therefore, 14 is the missing term.  
 
(ii)    
For this A.P., a2 = 13 and a4 = 3  
 
We know that, an = a + (n - 1) d  
a2 = a + (2 - 1) d  
13 = a + d …………………………(I)  
a4 = a + (4 - 1) d  
3 = a + 3d ………………………..(II)  
On subtracting (I) from (II), we obtain -10 = 2d  
d = -5  
From equation (I), we obtain  
13 = a + (-5)  
a = 18  
a3 = 18 + (3 - 1) (-5)  
= 18 + 2 (-5) = 18 - 10 = 8  
Therefore, the missing terms are 18 and 8 respectively.  
 
(iii)   
 
For this A.P.,  
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FAQs on NCERT Solutions, Exercise 5.2, Arithmetic Progression, Class 10 (Mathematics)

1. What is an arithmetic progression?
Ans. An arithmetic progression is a sequence of numbers in which the difference between any two consecutive terms is constant. This constant difference is called the common difference.
2. How can we find the nth term of an arithmetic progression?
Ans. To find the nth term of an arithmetic progression, we use the formula: nth term = first term + (n-1) * common difference Where the first term is the initial term of the sequence and the common difference is the difference between any two consecutive terms.
3. Can an arithmetic progression have a negative common difference?
Ans. Yes, an arithmetic progression can have a negative common difference. In an arithmetic progression, the common difference can be either positive or negative. A negative common difference indicates that the terms of the progression are decreasing.
4. How can we find the sum of the first 'n' terms of an arithmetic progression?
Ans. The sum of the first 'n' terms of an arithmetic progression can be found using the formula: Sum = (n/2) * (first term + last term) Where 'n' is the number of terms, the first term is the initial term of the sequence, and the last term is the nth term of the sequence.
5. Can an arithmetic progression have a common difference of zero?
Ans. Yes, an arithmetic progression can have a common difference of zero. In such a case, all the terms of the progression will be the same, resulting in a constant sequence.
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