In October, Oliver gave his wife, Abi, $9500 for household expenditure. Abi spent 50% of the sum on rental, 20% on food and saved the rest. In November, Oliver reduced the sum he gave to Abi. Abi 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 November. By what percentage was the sum given to Abi reduced by?

	Rental	Food	Savings	Total
Before	50%	20%	30%	$9500
Change		- 6%	- ?	- ?
After	50%	14%
Comparing the amounts spent in November	80 u		20 u	100 u

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

Amount that Oliver reduced on food in percent
= 30% x 20%
= ³⁰₁₀₀ x 20
= 6%

Total amount that Oliver spent on rental and food in percent
= 50% + 14%
= 64%

100% → 9500

1% → 9500 ÷ 100 = 95

64% → 64 x  95 = 6080

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

80 u = 64% 

80 u = 6080

1 u = 6080 ÷ 80 = 76

Amount that Oliver gave to Abi in November
= 100 u
= 100 x 76
= $7600

Amount that Abi received less from Oliver from October to November
= 9500 - 7600
= $1900

Percentage that the sum given to Abi was reduced by from October to November
= ¹⁹⁰⁰₉₅₀₀ x 100%
= 20%

Answer(s): 20%