A spends 65% of his income. His income is increased by 20.1% and the expenditure is increased by20%. By what percent (correct to one decimal place ) does his saving increase or decrease ?

Increase by 20.3%

Let, the income = Rs. 100x

So,  Expenditure = Rs. 65x

Savings = (100x - 65x) = 35x

His new income = 100x + (20.1% of 100x) = Rs. 120.1x

His new expenditure = 65x + (20% of 65x) = Rs. 78x

The new savings = 120.1x - 78x = Rs. 42.1x

The gain percentage of savings =\(\frac{42.1x - 35x}{35x}\) × 100 = 20.28% 

= 20.3% (correct to one decimal place)

∴ His saving increases by 20.3%