All questions of Linear Equations for SSC CGL Exam
Understanding Sherry's Savings
Sherry starts saving on March 1st, 2016, with an initial amount of 1 unit. Starting from March 2nd, he saves an additional 1 unit every day. This means his savings for each day can be calculated as follows:
- **March 1st**: 1 unit
- **March 2nd**: 2 units
- **March 3rd**: 3 units
- **March 4th**: 4 units
- ...
- **March n**: n units
Calculating Total Savings
To find the total savings by a specific date, we can use the formula for the sum of the first n natural numbers:
\[ \text{Total Savings} = 1 + 2 + 3 + ... + n = \frac{n(n + 1)}{2} \]
Where n is the total number of days since March 1st.
Perfect Squares
We want to identify the first date after March 1st, 2016, where the total savings becomes a perfect square.
Checking Dates
1. **March 1**: \( \text{Total} = 1 \) (Perfect Square)
2. **March 2**: \( \text{Total} = 1 + 2 = 3 \) (Not a Perfect Square)
3. **March 3**: \( \text{Total} = 1 + 2 + 3 = 6 \) (Not a Perfect Square)
4. **March 4**: \( \text{Total} = 10 \) (Not a Perfect Square)
5. **March 5**: \( \text{Total} = 15 \) (Not a Perfect Square)
6. **March 6**: \( \text{Total} = 21 \) (Not a Perfect Square)
7. **March 7**: \( \text{Total} = 28 \) (Not a Perfect Square)
8. **March 8**: \( \text{Total} = 36 \) (Perfect Square: \(6^2\))
The first date after March 1st when the total savings is a perfect square is **March 8th, 2016**.
Conclusion
Since the options provided do not include March 8th, the correct answer is **None of these** (option 'D').
Let us assume Ram has R rupees and Mohan has M rupees.
According to question,
If Ram gives 30 rupees to Mohan, then
Ram has left money = R - 30 and Mohan has money = M + 30
Then Mohan will have twice the money left with Ram,
M + 30 = 2(R - 30)
M + 30 = 2R - 60
2R - M = 90................................(1)
Again According to question,
if Mohan gives 10 rupees to Ram, then
Mohan has left the money = M - 10 and Ram has the money = R + 10
Then According to question,
Ram will have thrice as much as is left with Mohan,
R + 10 = 3 (M - 10 )
⇒ R + 10 = 3M - 30
⇒ 3M - R = 10 + 30
⇒ 3M - R = 40..................................(2)
After Multiplying 2 with Equation (2) , add with the equation (1),
6M - 2R + 2R - M = 80 + 90
⇒ 6M - M = 170
⇒ 5M = 170
⇒ M = 170/5
⇒ M = 34
Put the value of M in equation (1), we will get
⇒ 2R - 34 = 90
⇒ 2R = 90 + 34
⇒ 2R = 124
⇒ R = 124/2
⇒ R = 62
Let the number of rice bowls be a, the number of juice bowls be b, and the number of meat bowls be c.
According to question,
a + b + c = 65........................(1)
The total number of guests = 2a
The total number of guests = 3b
The total number of guests = 4c
So the total number of guests will be same in the party.
2a = 3b = 4c..........................(2)
As per Equation (2)
b = 2a/3................................(3)
c = 2a/4 = a/2......................(4)
Now put the value of b and c from Equation (3), (4) in Equation (1),
a + 2a/3 + a/2 = 65
(6a + 4a + 3a)/6 = 65
13a = 65 x 6
a = 5 x 6 = 30
Put the value of a in equation (3) and (4) in order to get the value of b and c,
b = 2 x 30/3 = 2 x 10 = 20
c = 30/2 = 15
The Total number of Guests = 2a = 3b = 4c = 60
Let us assume the numbers of days of tour before extending the tour are D and daily expenses is E.
According to question,
Total expenses on tour = per day expenses x total number of days
Total expenses on tour = E x D = ED
360 = ED
⇒ ED = 360
⇒ E = 360/D .................(1)
Again according to question,
After extending the tour by 4 days, Number of days of tour = D + 4
Expenses will be reduced by 3 rupees, then everyday expenses = E - 3
so total expenses = (D + 4) x (E - 3)
360 = (D + 4) x (E - 3)
(D + 4) x (E - 3) = 360 .............................................(2)
Put the value of E in Equation (2). we will get,
(D + 4) x (360/D - 3) = 360
⇒ (D + 4) x ( (360 - 3D)/D ) = 360
⇒ (D + 4) x ( (360 - 3D) ) = 360 x D
⇒ (D + 4) x (360 - 3D) = 360 x D
After multiplication by algebra law,
⇒ 360 x D - 3D x D + 4 x 360 - 4 x 3D = 360D
⇒ 360 x D - 3D + 1440 - 12D = 360D
⇒ - 3D + 1440 - 12D = 360D - 360 x D
⇒ - 3D + 1440 - 12D = 0
⇒ 3D - 1440 + 12D = 0
⇒ D - 480 + 4D = 0
⇒ D + 4D - 480 = 0
⇒ D + 24D - 20D - 480 = 0
⇒ D(D + 24) - 20(D + 24) = 0
⇒ (D + 24) (D - 20) = 0
Either (D + 24) = 0 or (D - 20) = 0
So D = - 24 or D = 20
But days cannot be negative so D = 20 days.
Let us assume the number be 3p , 3(p+1) and 3(p+2)
According to question,
3p + 3(p+1) + 3(p+2) = 72
⇒ 3p + 3p + 3 +3p + 6 = 72
⇒ 9p +9 = 72
⇒ 9p = 72 - 9
⇒ 9p = 63
⇒ p = 63/9 = 7
∴ Largest number = 3(p + 2)
Put the value of p in above equation.
⇒ Largest number = 3 x (7 + 2)
⇒ Largest number = 3 x 9
⇒ Largest number = 27