Marion, Xuan and Rachel bought a present for their buddy. They shared the cost equally between them. Marion used ¹₃ of her savings, Xuan used ³₈ of her savings and Rachel used ⁴₅ of her savings. Marion and Rachel had $540 left. How much did each girl pay for the present?
The amount spent by each girl is the same.  Make the numerators the same.
LCM of 1, 3 and 4 = 12

1x123x12 of Marion's savings = 3x48x4 of Xuan's savings = 4x35x3 of Rachel savings
1236 of Marion's savings = 1232 of Xuan's savings = 1215 of Rachel's savings

	Marion	Xuan	Rachel
Before	36 u	32 u	15 u
Change	- 12 u	- 12 u	- 12 u
After	24 u	20 u	3 u

Savings that Marion had left
= 36 u - 12 u
= 24 u

Savings that Rachel had left
= 15 u - 12 u
= 3 u

Total savings that Marion and Rachel had left
= 24 u + 3 u
= 27 u

27 u = 540

1 u = 540 ÷ 27 = 20

Amount that each girl paid
= 12 u
= 12 x 20
= $240

Answer(s): $240