In January, Oliver gave his wife, Jean, $10000 for household expenditure. Jean spent 60% of the sum on rental, 10% on food and saved the rest. In February, Oliver reduced the sum he gave to Jean. Jean spent the same amount on rental and reduced the amount she spent on food by 20%. She saved the remaining 20% of the sum given to her in February. By what percentage was the sum given to Jean reduced by?

	Rental	Food	Savings	Total
Before	60%	10%	30%	$10000
Change		- 2%	- ?	- ?
After	60%	8%
Comparing the amounts spent in February	80 u		20 u	100 u

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

Amount that Oliver reduced on food in percent
= 20% x 10%
= ²⁰₁₀₀ x 10
= 2%

Total amount that Oliver spent on rental and food in percent
= 60% + 8%
= 68%

100% → 10000

1% → 10000 ÷ 100 = 100

68% → 68 x  100 = 6800

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

80 u = 68% 

80 u = 6800

1 u = 6800 ÷ 80 = 85

Amount that Oliver gave to Jean in February
= 100 u
= 100 x 85
= $8500

Amount that Jean received less from Oliver from January to February
= 10000 - 8500
= $1500

Percentage that the sum given to Jean was reduced by from January to February
= ¹⁵⁰⁰₁₀₀₀₀ x 100%
= 15%

Answer(s): 15%