The ratio between expenditure and saving is 3 : 2 when income is increased by 15%, expenditure 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 × \(\frac{15}{100}\) =0. 18R

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