A person saves 10% of his monthly income. If his monthly income increases by 20%, he saves 20% more than his previous savings. The percentage increase in his expenditure is ____.

Correct option is B

Given:
The person saves 10% of his monthly income initially.
His income increases by 20%.
The new savings are 20% more than the previous savings.
Formula Used:
Income = Saving + Expenditure
Solution:
Let person income is 100.
Saving = $$100 \times \frac{10}{100}$$​ = 10
Expenditure =  100 - 10 = 90

New income = 100 + $$100 \times \frac{20}{100}$$ = 100 + 20 = 120

New saving = 10 + $$10 \times \frac{20}{100}$$  = 10 + 2 = 12

New expenditure = 120 - 12 = 108

Increaese expenditure = 108 - 90 = 18

Increaese expenditure% = $$\frac{18}{90}\times 100 = 20\%$$

Thus, the correct answer is (b).