Billy and Ken were given some allowances each. If Billy spent $11 each day and Ken spent $33 each day, Billy would still have $2472 left when Ken spent all his allowance. If Billy spent $33 each day and Ken spent $11 each day, Billy would still have $96 left when Ken spent all his allowance.
- How much allowance did Billy receive?
- How much allowance did Ken receive?
|
Case 1 |
Case 2 |
|
Billy |
Ken |
Billy |
Ken |
Before |
1 u + 2472 |
3 u |
3 p + 96 |
1 p |
Change |
- 1 u |
- 3 u |
- 3 p |
- 1 p |
After |
2472 |
0 |
96 |
0 |
(a)
Simplify the ratio.
11 : 33 = 1 : 3
The allowance that Ken had at first is the same for Case 1 and Case 2.
1 p = 3 u
3 p = 9 u
The allowance that Billy had at first is the same for Case 1 and Case 2.
9 u + 96 = 1 u + 2472
9 u - 1 u = 2472 - 96
8 u = 2376
1 u = 2376 ÷ 8 = 297
Allowance that Billy received
= 1 u + 2472
= 297 + 2472
= $2769
(b)
Allowance that Ken received
= 3 u
= 3 x 297
= $891
Answers: (a) $2769; (b) $891