Xandra, Ivory, Roshel and Xylia jointly contributed to the cost of a present for their sister. Xandra's contribution is ¹₆ of the total contribution made by the four girls. The ratio of Xylia's contribution to the total of Ivory's and Roshel's contribution is 4 : 1. What is the total contribution by the four girls if Ivory's contribution is ²₃ of Roshel's contribution and the total amount contributed by Xandra and Xylia is $375?

Xandra	Ivory	Roshel	Xylia	Total
1x5	5x5			6x5
	1x5		4x5
	2x1	3x1
5 u	2 u	3 u	20 u	30 u

Working backwards.

Total amount that Ivory and Roshel had is the combined repeated identity.
LCM of 1 and 5 = 5

Total amount that Ivory, Roshel and Xylia had is the next combined repeated identity.
LCM of 5 and 5 = 25 

Total amount contributed by Xandra and Xylia
= 5 u + 20 u
= 25 u

25 u = 375

1 u = 375 ÷ 25 = $15

Total contribution by the four girls
= 30 u
= 30 x 15
= $450

Answer(s): $450