In September, Daniel gave his wife, Opal, $10000 for household expenditure. Opal spent 60% of the sum on rental, 10% on food and saved the rest. In October, Daniel reduced the sum he gave to Opal. Opal spent the same amount on rental and reduced the amount she spent on food by 10%. She saved the remaining 25% of the sum given to her in October. By what percentage was the sum given to Opal reduced by?

	Rental	Food	Savings	Total
Before	60%	10%	30%	$10000
Change		- 1%	- ?	- ?
After	60%	9%
Comparing the amounts spent in October	75 u		25 u	100 u

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

Amount that Daniel reduced on food in percent
= 10% x 10%
= ¹⁰₁₀₀ x 10
= 1%

Total amount that Daniel spent on rental and food in percent
= 60% + 9%
= 69%

100% → 10000

1% → 10000 ÷ 100 = 100

69% → 69 x  100 = 6900

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

75 u = 69% 

75 u = 6900

1 u = 6900 ÷ 75 = 92

Amount that Daniel gave to Opal in October
= 100 u
= 100 x 92
= $9200

Amount that Opal received less from Daniel from September to October
= 10000 - 9200
= $800

Percentage that the sum given to Opal was reduced by from September to October
= ⁸⁰⁰₁₀₀₀₀ x 100%
= 8%

Answer(s): 8%