The ratio between the monthly income and the expenditure of Vaidic is 8 ∶ 5. If his income increases by 20% and his expenditure increases by 30%, then find the percentage increase or decrease in his monthly savings.

Question

Question

This question was previously asked in

SSC CGL 2023 Tier-I Official Paper (Held On: 14 Jul 2023 Shift 4)

Answer 1

Given:

The ratio between the monthly income and the expenditure of Vaidic is 8 ∶ 5

His income increases by 20% and his expenditure increases by 30%.

Calculations:

Let the monthly income and the expenditure of Vaidic be 8a and 5a respectively.

Savings = 8a - 5a = 3a.

Increase in income from next year,

I = 8a(1 + 20%)

⇒ I = 8a(1 + 0.20)

⇒ I = 9.6a

Increase in expenses from next year,

E = 5a(1 + 30%)

⇒ E = 5a(1 + 0.30)

⇒ E = 5a(1.30) = Rs. 6.5a

Savings from next year,

S = 9.6a - 6.5a = Rs. 3.1a

The total increase in savings,

S% = [(3.1a - 3a/3a)] × 100

⇒ S% = 10/3

⇒ S = 3(1/3)

∴ The percentage increase in his saving is 3(1/3)%.