In April, Ian gave his wife, Betty, $4000 for household expenditure. Betty spent 60% of the sum on rental, 20% on food and saved the rest. In May, Ian reduced the sum he gave to Betty. Betty spent the same amount on rental and reduced the amount she spent on food by 30%. She saved the remaining 20% of the sum given to her in May. By what percentage was the sum given to Betty reduced by?

	Rental	Food	Savings	Total
Before	60%	20%	20%	$4000
Change		- 6%	- ?	- ?
After	60%	14%
Comparing the amounts spent in May	80 u		20 u	100 u

Amount that Ian saved in percent
= 100% - 60% - 20%
= 20%

Amount that Ian reduced on food in percent
= 30% x 20%
= ³⁰₁₀₀ x 20
= 6%

Total amount that Ian spent on rental and food in percent
= 60% + 14%
= 74%

100% → 4000

1% → 4000 ÷ 100 = 40

74% → 74 x  40 = 2960

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

80 u = 74% 

80 u = 2960

1 u = 2960 ÷ 80 = 37

Amount that Ian gave to Betty in May
= 100 u
= 100 x 37
= $3700

Amount that Betty received less from Ian from April to May
= 4000 - 3700
= $300

Percentage that the sum given to Betty was reduced by from April to May
= ³⁰⁰₄₀₀₀ x 100%
= 7.5%

Answer(s): 7.5%