Adam and Bryan have a total of $104.
Adam spends
12 of his money and
Bryan spends
18 of his money.
They spend $28 altogether.
- How much does Adam have at first?
- How much does Bryan have in the end?
|
Adam |
Bryan |
Before |
2 u |
8 p |
Change |
- 1 u |
- 1 p |
After |
1 u |
7 p |
(a)
Amount that Adam has at first = 2 u
Amount that Bryan has at first = 8 p
Total amount that they have = 2 u + 8 p = 104 --- (1)
Total amount that they spend = 1 u + 1 p = 28 --- (2)
(2)
x 8 8 u + 8 p = 224 --- (3)
(3) - (1)
(8 u + 8 p) - (2 u + 8 p) = 224 - 104
8 u + 8 p - 2 u - 8 p = 224 - 104
8 u - 2 u + 8 p - 8 p = 120
8 u - 2 u = 120
6 u = 120
1 u = 120 ÷ 6 = 20
Substitute 1 u = 20 into (1).
2 u + 8 p = 104
2 x 20 + 8 p = 104
40 + 8 p = 104
8 p = 104 - 40 = 64
1 p = 64 ÷ 8 = 8
Amount that Adam has at first
= 2 u
= 2 x 20
= $40
(b)
Amount that Bryan has in the end
= 8 p - 1 p
= 7 p
= 7 x 8
= $56
Answer(s): (a) $40; (b) $56