Adam and Bryan have a total of $237.
Adam spends
15 of his money and
Bryan spends
18 of his money.
They spend $30 altogether.
- How much does Adam have at first?
- How much does Bryan have in the end?
|
Adam |
Bryan |
Before |
5 u |
8 p |
Change |
- 1 u |
- 1 p |
After |
4 u |
7 p |
(a)
Amount that Adam has at first = 5 u
Amount that Bryan has at first = 8 p
Total amount that they have = 5 u + 8 p = 237 --- (1)
Total amount that they spend = 1 u + 1 p = 30 --- (2)
(2)
x 8 8 u + 8 p = 240 --- (3)
(3) - (1)
(8 u + 8 p) - (5 u + 8 p) = 240 - 237
8 u + 8 p - 5 u - 8 p = 240 - 237
8 u - 5 u + 8 p - 8 p = 3
8 u - 5 u = 3
3 u = 3
1 u = 3 ÷ 3 = 1
Substitute 1 u = 1 into (1).
5 u + 8 p = 237
5 x 1 + 8 p = 237
5 + 8 p = 237
8 p = 237 - 5 = 232
1 p = 232 ÷ 8 = 29
Amount that Adam has at first
= 5 u
= 5 x 1
= $5
(b)
Amount that Bryan has in the end
= 8 p - 1 p
= 7 p
= 7 x 29
= $203
Answer(s): (a) $5; (b) $203