Usha, Tiffany, Shiyun and Jaslyn went to buy a present for their older brother. They shared the cost equally among themselves. However, Jaslyn forgot to bring her money. So, the other 3 girls paid for the present first. Shiyun paid ⁷₉ of the amount Usha and Tiffany paid. Tiffany paid $3 more than Usha. The next day, Jaslyn returned $15 to Shiyun and some money to Usha and Tiffany. How much did Jaslyn return to

1. Usha?
2. Tiffany?

	Usha	Tiffany	Shiyun	Jaslyn	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 + 3
Amounts that each girl paid for Jaslyn first	- ?	- ?	- 15	+ 15 + ?
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 = 15

1 u = 15 ÷ 3 = 5

Total amount that Usha and Tiffany paid at first
= 9 u
= 9 x 5
= $45

1 p + 1 p + 3 = 45
2 p = 45 - 3
2 p = 42

1 p = 42 ÷ 2 = 21

Amount that Jaslyn needed to pay Usha
= 1 p - 4 u
= 21 - 4 x 5
= 21 - 20
= $1

(b)
Amount that Jaslyn needed to pay Tiffany
= (1 p + 3) - 4 u
= (21 + 3) - 4 x 5
= 24 - 20
= $4

Answer(s): (a) $1; (b) $4