Opal, Barbara, Usha and Jen jointly contributed to the cost of a present for their classmate. Opal's contribution is ²₉ of the total contribution made by the four girls. The ratio of Jen's contribution to the total of Barbara's and Usha's contribution is 3 : 2. What is the total contribution by the four girls if Barbara's contribution is ¹₆ of Usha's contribution and the total amount contributed by Opal and Jen is $93?

Opal	Barbara	Usha	Jen	Total
2x5	7x5			9x5
	2x7		3x7
	1x2	6x2
10 u	2 u	12 u	21 u	45 u

Working backwards.

Total amount that Barbara and Usha had is the combined repeated identity.
LCM of 2 and 7 = 14

Total amount that Barbara, Usha and Jen had is the next combined repeated identity.
LCM of 7 and 5 = 35 

Total amount contributed by Opal and Jen
= 10 u + 21 u
= 31 u

31 u = 93

2 u = 93 ÷ 31 = $3

Total contribution by the four girls
= 45 u
= 45 x 3
= $135

Answer(s): $135