Dana, Abi, Lynn and Barbara jointly contributed to the cost of a present for their colleague. Dana's contribution is ³₄ of the total contribution made by the four girls. The ratio of Barbara's contribution to the total of Abi's and Lynn's contribution is 2 : 1. What is the total contribution by the four girls if Abi's contribution is ¹₄ of Lynn's contribution and the total amount contributed by Dana and Barbara is $110?

Dana	Abi	Lynn	Barbara	Total
3x15	1x15			4x15
	1x5		2x5
	1x1	4x1
45 u	1 u	4 u	10 u	60 u

Working backwards.

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

Total amount that Abi, Lynn and Barbara had is the next combined repeated identity.
LCM of 1 and 15 = 15 

Total amount contributed by Dana and Barbara
= 45 u + 10 u
= 55 u

55 u = 110

1 u = 110 ÷ 55 = $2

Total contribution by the four girls
= 60 u
= 60 x 2
= $120

Answer(s): $120