Lucy spent ²₅ of her salary on a kettle and ³₄ of the remainder on a washing machine. If she saved the remaining $78, how much was her salary?
Fraction of the salary spent on the kettle = ²₅

Fraction of the salary on the remainder
= 1 - ²₅
= ³₅

Fraction of the remainder on savings
= 1 - ³₄
= ¹₄

Kettle	Remainder		Total
2x4	3x4		5x4
	Washing Machine	Savings
	3x3	1x3
8 u	9 u	3 u	20 u

The remainder and the total amount on the washing machine and the savings are the same. Make the remainder and the total amount on the washing machine and the savings the same.  LCM of 3 and 4 is 12.

Total salary = 20 u

Amount spent of the kettle = 8 u
Amount spent on the washing machine = 9 u
Amount of savings = 3 u

3 u = 78

1 u = 78 ÷ 3 = 26

Lucy's salary
= 20 u
= 20 x 26
= $520

Answer(s): $520