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

	Rental	Food	Savings	Total
Before	50%	10%	40%	$8000
Change		- 3%	- ?	- ?
After	50%	7%
Comparing the amounts spent in December	80 u		20 u	100 u

Amount that Gabriel saved in percent
= 100% - 50% - 10%
= 40%

Amount that Gabriel reduced on food in percent
= 30% x 10%
= ³⁰₁₀₀ x 10
= 3%

Total amount that Gabriel spent on rental and food in percent
= 50% + 7%
= 57%

100% → 8000

1% → 8000 ÷ 100 = 80

57% → 57 x  80 = 4560

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

80 u = 57% 

80 u = 4560

1 u = 4560 ÷ 80 = 57

Amount that Gabriel gave to Zoe in December
= 100 u
= 100 x 57
= $5700

Amount that Zoe received less from Gabriel from November to December
= 8000 - 5700
= $2300

Percentage that the sum given to Zoe was reduced by from November to December
= ²³⁰⁰₈₀₀₀ x 100%
= 28.75%

Answer(s): 28.75%