Kathy, Joelle, Rachel and Sarah went to buy a gift for their father. They shared the cost equally among themselves. However, Sarah forgot to bring her money. So, the other 3 girls paid for the gift first. Rachel paid
79 of the amount Kathy and Joelle paid. Joelle paid $6 more than Kathy. The next day, Sarah returned $30 to Rachel and some money to Kathy and Joelle. How much did Sarah return to
- Kathy?
- Joelle?
|
Kathy |
Joelle |
Rachel |
Sarah |
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 + 6
|
|
|
|
Amounts that each girl paid for Sarah first |
- ? |
- ? |
- 30
|
+ 30 + ? |
|
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 Rachel paid
= 7 u - 4 u
= 3 u
3 u = 30
1 u = 30 ÷ 3 = 10
Total amount that Kathy and Joelle paid at first
= 9 u
= 9 x 10
= $90
1 p + 1 p + 6 = 90
2 p = 90 - 6
2 p = 84
1 p = 84 ÷ 2 = 42
Amount that Sarah needed to pay Kathy
= 1 p - 4 u
= 42 - 4 x 10
= 42 - 40
= $2
(b)
Amount that Sarah needed to pay Joelle
= (1 p + 6) - 4 u
= (42 + 6) - 4 x 10
= 48 - 40
= $8
Answer(s): (a) $2; (b) $8