Yoko, Sarah and Eva had a sum of money. The amount of money Yoko had was ²₅ of the amount of money Sarah had. The ratio of the amount of money Sarah had to the total amount of money Eva and Sarah had was 2: 7. After Eva gave $30 to Sarah, she had as much money as Sarah. How much more money did Eva have than Yoko in the end?

Yoko	Sarah	Eva
2x2 = 4 u	5x2 = 10 u
	2x5 = 10 u	5x5 = 25 u
4 u	10 u	25 u

The amount that Sarah had is the repeated identity. Make the amount that Sarah had the same.  LCM of 5 and 2 is 10.

	Yoko	Sarah	Eva
Before	4 u	10 u	25 u
Change	No change	+ 30	- 30
After	4 u	10 u + 30	25 u - 30

The amount that Eva and Sarah had in the end is the same.

25 u - 30 = 10 u + 30
25 u - 10 u = 30 + 30 
15 u = 60

1 u = 60 ÷ 15 = 4

Amount that Eva had more than Yoko in the end
= 25 u - 30 - 4 u
= 21 u - 30
= 21 x 4 - 30
= 84 - 30
= $54

Answer(s): $54