Priya spends 80% of her income and saves the rest. Her income then rises by 25% and her spending rises by 15%. By what percentage do her savings rise?

Explanation

1. 01

   Let the old income be 100: spending 80, savings 20.

2. 02

   New income = 125; new spending = $80 \times 1.15 = 92$.

3. 03

   New savings = $125 - 92 = 33$, a rise of 13.

4. 04

   Percentage rise = $\frac{13}{20} \times 100 = 65\%$.