John and Luis were given some allowances each. If John spent $17 each day and Luis spent $51 each day, John would still have $2124 left when Luis spent all his allowance. If John spent $51 each day and Luis spent $17 each day, John would still have $84 left when Luis spent all his allowance.
- How much allowance did John receive?
- How much allowance did Luis receive?
|
Case 1 |
Case 2 |
|
John |
Luis |
John |
Luis |
Before |
1 u + 2124 |
3 u |
3 p + 84 |
1 p |
Change |
- 1 u |
- 3 u |
- 3 p |
- 1 p |
After |
2124 |
0 |
84 |
0 |
(a)
Simplify the ratio.
17 : 51 = 1 : 3
The allowance that Luis 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 + 84 = 1 u + 2124
9 u - 1 u = 2124 - 84
8 u = 2040
1 u = 2040 ÷ 8 = 255
Allowance that John received
= 1 u + 2124
= 255 + 2124
= $2379
(b)
Allowance that Luis received
= 3 u
= 3 x 255
= $765
Answers: (a) $2379; (b) $765