George and Michael were given some allowances each. If George spent $15 each day and Michael spent $30 each day, George would still have $999 left when Michael spent all his allowance. If George spent $30 each day and Michael spent $15 each day, George would still have $99 left when Michael spent all his allowance.
- How much allowance did George receive?
- How much allowance did Michael receive?
|
Case 1 |
Case 2 |
|
George |
Michael |
George |
Michael |
Before |
1 u + 999 |
2 u |
2 p + 99 |
1 p |
Change |
- 1 u |
- 2 u |
- 2 p |
- 1 p |
After |
999 |
0 |
99 |
0 |
(a)
Simplify the ratio.
15 : 30 = 1 : 2
The allowance that Michael had at first is the same for Case 1 and Case 2.
1 p = 2 u
2 p = 4 u
The allowance that George had at first is the same for Case 1 and Case 2.
4 u + 99 = 1 u + 999
4 u - 1 u = 999 - 99
3 u = 900
1 u = 900 ÷ 3 = 300
Allowance that George received
= 1 u + 999
= 300 + 999
= $1299
(b)
Allowance that Michael received
= 2 u
= 2 x 300
= $600
Answers: (a) $1299; (b) $600