In July, Ken gave his wife, Eva, $6000 for household expenditure. Eva spent 60% of the sum on rental, 30% on food and saved the rest. In August, Ken reduced the sum he gave to Eva. Eva 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 August. By what percentage was the sum given to Eva reduced by?

	Rental	Food	Savings	Total
Before	60%	30%	10%	$6000
Change		- 9%	- ?	- ?
After	60%	21%
Comparing the amounts spent in August	90 u		10 u	100 u

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

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

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

100% → 6000

1% → 6000 ÷ 100 = 60

81% → 81 x  60 = 4860

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

90 u = 81% 

90 u = 4860

1 u = 4860 ÷ 90 = 54

Amount that Ken gave to Eva in August
= 100 u
= 100 x 54
= $5400

Amount that Eva received less from Ken from July to August
= 6000 - 5400
= $600

Percentage that the sum given to Eva was reduced by from July to August
= ⁶⁰⁰₆₀₀₀ x 100%
= 10%

Answer(s): 10%