In May, Henry gave his wife, Mary, $2500 for household expenditure. Mary spent 50% of the sum on rental, 20% on food and saved the rest. In June, Henry reduced the sum he gave to Mary. Mary spent the same amount on rental and reduced the amount she spent on food by 20%. She saved the remaining 25% of the sum given to her in June. By what percentage was the sum given to Mary reduced by?

	Rental	Food	Savings	Total
Before	50%	20%	30%	$2500
Change		- 4%	- ?	- ?
After	50%	16%
Comparing the amounts spent in June	75 u		25 u	100 u

Amount that Henry saved in percent
= 100% - 50% - 20%
= 30%

Amount that Henry reduced on food in percent
= 20% x 20%
= ²⁰₁₀₀ x 20
= 4%

Total amount that Henry spent on rental and food in percent
= 50% + 16%
= 66%

100% → 2500

1% → 2500 ÷ 100 = 25

66% → 66 x  25 = 1650

The total amount that Henry spent on rental and food is repeated. 

75 u = 66% 

75 u = 1650

1 u = 1650 ÷ 75 = 22

Amount that Henry gave to Mary in June
= 100 u
= 100 x 22
= $2200

Amount that Mary received less from Henry from May to June
= 2500 - 2200
= $300

Percentage that the sum given to Mary was reduced by from May to June
= ³⁰⁰₂₅₀₀ x 100%
= 12%

Answer(s): 12%