Sabrina, Anna, Yoko and Barbara went to buy a present for their grandfather. They shared the cost equally among themselves. However, Barbara forgot to bring her money. So, the other 3 girls paid for the present first. Yoko paid ⁷₉ of the amount Sabrina and Anna paid. Anna paid $5 more than Sabrina. The next day, Barbara returned $21 to Yoko and some money to Sabrina and Anna. How much did Barbara return to

1. Sabrina?
2. Anna?

	Sabrina	Anna	Yoko	Barbara	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 + 5
Amounts that each girl paid for Barbara first	- ?	- ?	- 21	+ 21 + ?
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 Yoko paid 
= 7 u - 4 u
= 3 u

3 u = 21

1 u = 21 ÷ 3 = 7

Total amount that Sabrina and Anna paid at first
= 9 u
= 9 x 7
= $63

1 p + 1 p + 5 = 63
2 p = 63 - 5
2 p = 58

1 p = 58 ÷ 2 = 29

Amount that Barbara needed to pay Sabrina
= 1 p - 4 u
= 29 - 4 x 7
= 29 - 28
= $1

(b)
Amount that Barbara needed to pay Anna
= (1 p + 5) - 4 u
= (29 + 5) - 4 x 7
= 34 - 28
= $6

Answer(s): (a) $1; (b) $6