In July, Tommy gave his wife, Jean, $9000 for household expenditure. Jean spent 50% of the sum on rental, 20% on food and saved the rest. In August, Tommy reduced the sum he gave to Jean. Jean 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 August. By what percentage was the sum given to Jean reduced by?

	Rental	Food	Savings	Total
Before	50%	20%	30%	$9000
Change		- 6%	- ?	- ?
After	50%	14%
Comparing the amounts spent in August	80 u		20 u	100 u

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

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

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

100% → 9000

1% → 9000 ÷ 100 = 90

64% → 64 x  90 = 5760

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

80 u = 64% 

80 u = 5760

1 u = 5760 ÷ 80 = 72

Amount that Tommy gave to Jean in August
= 100 u
= 100 x 72
= $7200

Amount that Jean received less from Tommy from July to August
= 9000 - 7200
= $1800

Percentage that the sum given to Jean was reduced by from July to August
= ¹⁸⁰⁰₉₀₀₀ x 100%
= 20%

Answer(s): 20%