Raeann, Emma, Xandra and Yen jointly contributed to the cost of a present for their schoolmate. Raeann's contribution is ²₃ of the total contribution made by the four girls. The ratio of Yen's contribution to the total of Emma's and Xandra's contribution is 3 : 2. What is the total contribution by the four girls if Emma's contribution is ²₇ of Xandra's contribution and the total amount contributed by Raeann and Yen is $1521?

Raeann	Emma	Xandra	Yen	Total
2x45	1x45			3x45
	2x9		3x9
	2x2	7x2
90 u	4 u	14 u	27 u	135 u

Working backwards.

Total amount that Emma and Xandra had is the combined repeated identity.
LCM of 2 and 9 = 18

Total amount that Emma, Xandra and Yen had is the next combined repeated identity.
LCM of 1 and 45 = 45 

Total amount contributed by Raeann and Yen
= 90 u + 27 u
= 117 u

117 u = 1521

2 u = 1521 ÷ 117 = $13

Total contribution by the four girls
= 135 u
= 135 x 13
= $1755

Answer(s): $1755