In October, Zeph gave his wife, Zara, $8000 for household expenditure. Zara spent 50% of the sum on rental, 30% on food and saved the rest. In November, Zeph reduced the sum he gave to Zara. Zara spent the same amount on rental and reduced the amount she spent on food by 10%. She saved the remaining 20% of the sum given to her in November. By what percentage was the sum given to Zara reduced by?

	Rental	Food	Savings	Total
Before	50%	30%	20%	$8000
Change		- 3%	- ?	- ?
After	50%	27%
Comparing the amounts spent in November	80 u		20 u	100 u

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

Amount that Zeph reduced on food in percent
= 10% x 30%
= ¹⁰₁₀₀ x 30
= 3%

Total amount that Zeph spent on rental and food in percent
= 50% + 27%
= 77%

100% → 8000

1% → 8000 ÷ 100 = 80

77% → 77 x  80 = 6160

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

80 u = 77% 

80 u = 6160

1 u = 6160 ÷ 80 = 77

Amount that Zeph gave to Zara in November
= 100 u
= 100 x 77
= $7700

Amount that Zara received less from Zeph from October to November
= 8000 - 7700
= $300

Percentage that the sum given to Zara was reduced by from October to November
= ³⁰⁰₈₀₀₀ x 100%
= 3.75%

Answer(s): 3.75%