Justin and Billy were given some allowances each. If Justin spent $14 each day and Billy spent $42 each day, Justin would still have $1152 left when Billy spent all his allowance. If Justin spent $42 each day and Billy spent $14 each day, Justin would still have $32 left when Billy spent all his allowance.
- How much allowance did Justin receive?
- How much allowance did Billy receive?
|
Case 1 |
Case 2 |
|
Justin |
Billy |
Justin |
Billy |
Before |
1 u + 1152 |
3 u |
3 p + 32 |
1 p |
Change |
- 1 u |
- 3 u |
- 3 p |
- 1 p |
After |
1152 |
0 |
32 |
0 |
(a)
Simplify the ratio.
14 : 42 = 1 : 3
The allowance that Billy had at first is the same for Case 1 and Case 2.
1 p = 3 u
3 p = 9 u
The allowance that Justin had at first is the same for Case 1 and Case 2.
9 u + 32 = 1 u + 1152
9 u - 1 u = 1152 - 32
8 u = 1120
1 u = 1120 ÷ 8 = 140
Allowance that Justin received
= 1 u + 1152
= 140 + 1152
= $1292
(b)
Allowance that Billy received
= 3 u
= 3 x 140
= $420
Answers: (a) $1292; (b) $420