Sabrina, Esther, Shiyun and Winnie went to buy a souvenir for their younger brother. They shared the cost equally among themselves. However, Winnie forgot to bring her money. So, the other 3 girls paid for the souvenir first. Shiyun paid ⁷₉ of the amount Sabrina and Esther paid. Esther paid $4 more than Sabrina. The next day, Winnie returned $36 to Shiyun and some money to Sabrina and Esther. How much did Winnie return to

1. Sabrina?
2. Esther?

	Sabrina	Esther	Shiyun	Winnie	Total
Comparing the amounts 3 girls paid first	9 u		7 u		16 u
Comparing the amounts 2 girls paid first	1 p	1 p + 4
Amounts that each girl paid for Winnie first	- ?	- ?	- 36	+ 36 + ?
Comparing the amounts each girl should pay	1x4 = 4 u	1x4 = 4 u	1x4 = 4 u	1x4 = 4 u	4x4 = 16 u

(a)
The total amount that the 4 girls paid is repeated. Make the total amount the same.  LCM of 4 and 16 is 16.

Extra amount that Shiyun paid 
= 7 u - 4 u
= 3 u

3 u = 36

1 u = 36 ÷ 3 = 12

Total amount that Sabrina and Esther paid at first
= 9 u
= 9 x 12
= $108

1 p + 1 p + 4 = 108
2 p = 108 - 4
2 p = 104

1 p = 104 ÷ 2 = 52

Amount that Winnie needed to pay Sabrina
= 1 p - 4 u
= 52 - 4 x 12
= 52 - 48
= $4

(b)
Amount that Winnie needed to pay Esther
= (1 p + 4) - 4 u
= (52 + 4) - 4 x 12
= 56 - 48
= $8

Answer(s): (a) $4; (b) $8