Olivia, Anna, Marion and Zoe jointly contributed to the cost of a present for their schoolmate. Olivia's contribution is ³₅ of the total contribution made by the four girls. The ratio of Zoe's contribution to the total of Anna's and Marion's contribution is 3 : 1. What is the total contribution by the four girls if Anna's contribution is ¹₇ of Marion's contribution and the total amount contributed by Olivia and Zoe is $1080?

Olivia	Anna	Marion	Zoe	Total
3x16	2x16			5x16
	1x8		3x8
	1x1	7x1
48 u	1 u	7 u	24 u	80 u

Working backwards.

Total amount that Anna and Marion had is the combined repeated identity.
LCM of 1 and 8 = 8

Total amount that Anna, Marion and Zoe had is the next combined repeated identity.
LCM of 2 and 16 = 32 

Total amount contributed by Olivia and Zoe
= 48 u + 24 u
= 72 u

72 u = 1080

1 u = 1080 ÷ 72 = $15

Total contribution by the four girls
= 80 u
= 80 x 15
= $1200

Answer(s): $1200