Peter could save 10% of his income. But two years later when his income is increased by 20%, he could save the same amount only as before. By how much percent has his expenditure increased ?

Answer: Option B

Let original income - Rs. 100
Then, saving = Rs. 10 and expenditure = Rs. 90
New income = Rs. 120
New saving = Rs. 10
New expenditure = Rs. (120 - 10) = Rs. 110
Increase in expenditure = Rs. (110 - 90) = Rs. 20
∴ Income % :
$$\begin{array}{rl}& =\left(\frac{20}{90}\times 100\right)\%\\ & =22\frac{2}{9}\%\end{array}$$