Question

Devdatta spends 75% of his income. If his income is increased by 20% and he increases his expenditure by 10%, then what percent is the increase in his savings?

Answer 1

 Let the income of Devdatta

= Rs. 100 .

His expenditure $=75 \%$ of 100

$=$ Rs. 75

$\therefore$ His savings $=$ Rs. $(100-75)$

$=$ Rs. 25

Now his new income

$=100+20 \%$ of 100

$=100+20=$ Rs. 120

his new expenditure

$=$ Rs. $75+10 \%$ of 75

$=$ Rs. $75+7.50$

$=$ Rs. $82 \cdot 50$

So, New savings

$=$ Rs. 120 - Rs. $82 \cdot 50$

$=$ Rs. $37.50$

- So, his increase in savings
$\begin{array}{l}=\frac{\text { Rs. } 37.50-\text { Rs. } 25}{\text { Rs. } 25} \times 100 \\=50 \% \text {; Ans. }\end{array}$