In April, Oscar gave his wife, Diana, $7500 for household expenditure. Diana spent 50% of the sum on rental, 20% on food and saved the rest. In May, Oscar reduced the sum he gave to Diana. Diana 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 May. By what percentage was the sum given to Diana reduced by?

	Rental	Food	Savings	Total
Before	50%	20%	30%	$7500
Change		- 4%	- ?	- ?
After	50%	16%
Comparing the amounts spent in May	75 u		25 u	100 u

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

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

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

100% → 7500

1% → 7500 ÷ 100 = 75

66% → 66 x  75 = 4950

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

75 u = 66% 

75 u = 4950

1 u = 4950 ÷ 75 = 66

Amount that Oscar gave to Diana in May
= 100 u
= 100 x 66
= $6600

Amount that Diana received less from Oscar from April to May
= 7500 - 6600
= $900

Percentage that the sum given to Diana was reduced by from April to May
= ⁹⁰⁰₇₅₀₀ x 100%
= 12%

Answer(s): 12%