Peter and Andy were given some allowances each. If Peter spent $12 each day and Andy spent $24 each day, Peter would still have $676 left when Andy spent all his allowance. If Peter spent $24 each day and Andy spent $12 each day, Peter would still have $100 left when Andy spent all his allowance.
- How much allowance did Peter receive?
- How much allowance did Andy receive?
|
Case 1 |
Case 2 |
|
Peter |
Andy |
Peter |
Andy |
Before |
1 u + 676 |
2 u |
2 p + 100 |
1 p |
Change |
- 1 u |
- 2 u |
- 2 p |
- 1 p |
After |
676 |
0 |
100 |
0 |
(a)
Simplify the ratio.
12 : 24 = 1 : 2
The allowance that Andy had at first is the same for Case 1 and Case 2.
1 p = 2 u
2 p = 4 u
The allowance that Peter had at first is the same for Case 1 and Case 2.
4 u + 100 = 1 u + 676
4 u - 1 u = 676 - 100
3 u = 576
1 u = 576 ÷ 3 = 192
Allowance that Peter received
= 1 u + 676
= 192 + 676
= $868
(b)
Allowance that Andy received
= 2 u
= 2 x 192
= $384
Answers: (a) $868; (b) $384