The ratio between expenditure and saving is 3 : 2 when income is increased by 15%, saving is increased by 9% , then by how much % should his expenditure increases .

19%

 let total income = 3R + 2R = 5R

 Increased Income =5R × $\frac{15}{100}$ =0. 75R

 Increased Saving =2R × $\frac{9}{100}$ =0. 18R

So, increased Expenditure =( 0.75R - 0.18R ) × $\frac{100}{3}$ = 19%