Fiona, Rachel, Natalie and Risa jointly contributed to the cost of a present for their brother. Fiona's contribution is ³₅ of the total contribution made by the four girls. The ratio of Risa's contribution to the total of Rachel's and Natalie's contribution is 5 : 1. What is the total contribution by the four girls if Rachel's contribution is ¹₄ of Natalie's contribution and the total amount contributed by Fiona and Risa is $140?

Fiona	Rachel	Natalie	Risa	Total
3x15	2x15			5x15
	1x5		5x5
	1x1	4x1
45 u	1 u	4 u	25 u	75 u

Working backwards.

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

Total amount that Rachel, Natalie and Risa had is the next combined repeated identity.
LCM of 2 and 15 = 30 

Total amount contributed by Fiona and Risa
= 45 u + 25 u
= 70 u

70 u = 140

1 u = 140 ÷ 70 = $2

Total contribution by the four girls
= 75 u
= 75 x 2
= $150

Answer(s): $150