In June, Will gave his wife, Winnie, $3000 for household expenditure. Winnie spent 60% of the sum on rental, 30% on food and saved the rest. In July, Will reduced the sum he gave to Winnie. Winnie spent the same amount on rental and reduced the amount she spent on food by 30%. She saved the remaining 10% of the sum given to her in July. By what percentage was the sum given to Winnie reduced by?

	Rental	Food	Savings	Total
Before	60%	30%	10%	$3000
Change		- 9%	- ?	- ?
After	60%	21%
Comparing the amounts spent in July	90 u		10 u	100 u

Amount that Will saved in percent
= 100% - 60% - 30%
= 10%

Amount that Will reduced on food in percent
= 30% x 30%
= ³⁰₁₀₀ x 30
= 9%

Total amount that Will spent on rental and food in percent
= 60% + 21%
= 81%

100% → 3000

1% → 3000 ÷ 100 = 30

81% → 81 x  30 = 2430

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

90 u = 81% 

90 u = 2430

1 u = 2430 ÷ 90 = 27

Amount that Will gave to Winnie in July
= 100 u
= 100 x 27
= $2700

Amount that Winnie received less from Will from June to July
= 3000 - 2700
= $300

Percentage that the sum given to Winnie was reduced by from June to July
= ³⁰⁰₃₀₀₀ x 100%
= 10%

Answer(s): 10%