In June, John gave his wife, Risa, $3500 for household expenditure. Risa spent 50% of the sum on rental, 20% on food and saved the rest. In July, John reduced the sum he gave to Risa. Risa 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 July. By what percentage was the sum given to Risa reduced by?

	Rental	Food	Savings	Total
Before	50%	20%	30%	$3500
Change		- 6%	- ?	- ?
After	50%	14%
Comparing the amounts spent in July	80 u		20 u	100 u

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

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

Total amount that John spent on rental and food in percent
= 50% + 14%
= 64%

100% → 3500

1% → 3500 ÷ 100 = 35

64% → 64 x  35 = 2240

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

80 u = 64% 

80 u = 2240

1 u = 2240 ÷ 80 = 28

Amount that John gave to Risa in July
= 100 u
= 100 x 28
= $2800

Amount that Risa received less from John from June to July
= 3500 - 2800
= $700

Percentage that the sum given to Risa was reduced by from June to July
= ⁷⁰⁰₃₅₀₀ x 100%
= 20%

Answer(s): 20%