A man spends 80% of his income and saves the rest. If his income and spending both increases by 10%, then what is the percentage change in his savings?

Let income of man = Rs. 100

Money spent = $$\frac{80}{100}\times100=Rs.$$ $$80$$

=> Money saved = $$(100-80)=Rs.$$ $$20$$

If his income and spending both increases by 10%, => New income = $$100+(\frac{10}{100}\times100)=Rs.$$ $$110$$

and new amount spent = $$80+(\frac{10}{100}\times80)=Rs.$$ $$88$$

=> Money saved = $$(110-88)=Rs.$$ $$22$$

$$\therefore$$ Percentage increase in his savings = $$\frac{(22-20)}{20}\times100$$

= $$2\times5=10\%$$

=> Ans - (A)