Rahim's expenditures and savings are in the ratio of 3 : 2. His income increases by 10%. His expenditure also increases by 12%. How much percent does his savings increase?

Question: Rahim's expenditures and savings are in the ratio of 3 : 2. His income increases by 10%. His expenditure also increases by 12%. How much percent does his savings increase?

Solution:
Let Rahim's expenditures be 3x and his savings be 2x
So, his income = 3x + 2x = 5x

Increased income = 110% of 5x = 5.5x
Increased expenditures = 112% of 3x = 3.36x

New savings = 5.5x - 3.36x = 2.14x

Increased savings = 2.14x - 2x = 0.14x

So, increases in percentage = (0.14x/2x) × 100 = 7%