John and Eric were given some allowances each. If John spent $15 each day and Eric spent $45 each day, John would still have $2312 left when Eric spent all his allowance. If John spent $45 each day and Eric spent $15 each day, John would still have $32 left when Eric spent all his allowance.
- How much allowance did John receive?
- How much allowance did Eric receive?
|
Case 1 |
Case 2 |
|
John |
Eric |
John |
Eric |
Before |
1 u + 2312 |
3 u |
3 p + 32 |
1 p |
Change |
- 1 u |
- 3 u |
- 3 p |
- 1 p |
After |
2312 |
0 |
32 |
0 |
(a)
Simplify the ratio.
15 : 45 = 1 : 3
The allowance that Eric had at first is the same for Case 1 and Case 2.
1 p = 3 u
3 p = 9 u
The allowance that John had at first is the same for Case 1 and Case 2.
9 u + 32 = 1 u + 2312
9 u - 1 u = 2312 - 32
8 u = 2280
1 u = 2280 ÷ 8 = 285
Allowance that John received
= 1 u + 2312
= 285 + 2312
= $2597
(b)
Allowance that Eric received
= 3 u
= 3 x 285
= $855
Answers: (a) $2597; (b) $855