In January, Luke gave his wife, Kimberly, $8000 for household expenditure. Kimberly spent 70% of the sum on rental, 10% on food and saved the rest. In February, Luke reduced the sum he gave to Kimberly. Kimberly 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 Kimberly reduced by?

	Rental	Food	Savings	Total
Before	70%	10%	20%	$8000
Change		- 2%	- ?	- ?
After	70%	8%
Comparing the amounts spent in February	80 u		20 u	100 u

Amount that Luke saved in percent
= 100% - 70% - 10%
= 20%

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

Total amount that Luke spent on rental and food in percent
= 70% + 8%
= 78%

100% → 8000

1% → 8000 ÷ 100 = 80

78% → 78 x  80 = 6240

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

80 u = 78% 

80 u = 6240

1 u = 6240 ÷ 80 = 78

Amount that Luke gave to Kimberly in February
= 100 u
= 100 x 78
= $7800

Amount that Kimberly received less from Luke from January to February
= 8000 - 7800
= $200

Percentage that the sum given to Kimberly was reduced by from January to February
= ²⁰⁰₈₀₀₀ x 100%
= 2.5%

Answer(s): 2.5%