Tiffany, Risa and Xuan shared $540 among themselves. Risa and Xuan shared ²₅ of the money equally. After Risa gave away some of her money to Tiffany, Xuan had 4 times as much money as Risa. How much money did Risa give to Tiffany?

	Risa	Xuan	Tiffany	Total
Before	1x4 = 4 u	1x4 = 4 u	3x4 = 12 u	20 u
Change	- 3 u	No change	+ 3 u
After	1x1 = 1 u	4x1 = 4 u	15 u	20 u

Risa and Xuan shared ²₅ of the money equally.

Fraction of the money that Risa and Xuan each had
= ²₅ ÷ 2
= ²₅ x ¹₂
= ¹₅

The amount that Xuan had remains unchanged.  The amount that Xuan had is the unchanged quantity. Make the amount that Xuan had the same. LCM of 1 and 4 is 4.

The amount that Risa and Xuan had at first is the same.

Total amount that they had at first
= 4 u + 4 u + 12 u
= 20 u

20 u = 540

1 u = 540 ÷ 20 = 27

Amount that Risa gave to Tiffany
= 4 u - 1 u
= 3 u
= 3 x 27
= $81

Answer(s): $81