Bryan and Adam have a total of $82.
Bryan spends
12 of his money and
Adam spends
18 of his money.
They spend $11 altogether.
- How much does Bryan have at first?
- How much does Adam have in the end?
|
Bryan |
Adam |
Before |
2 u |
8 p |
Change |
- 1 u |
- 1 p |
After |
1 u |
7 p |
(a)
Amount that Bryan has at first = 2 u
Amount that Adam has at first = 8 p
Total amount that they have = 2 u + 8 p = 82 --- (1)
Total amount that they spend = 1 u + 1 p = 11 --- (2)
(2)
x 8 8 u + 8 p = 88 --- (3)
(3) - (1)
(8 u + 8 p) - (2 u + 8 p) = 88 - 82
8 u + 8 p - 2 u - 8 p = 88 - 82
8 u - 2 u + 8 p - 8 p = 6
8 u - 2 u = 6
6 u = 6
1 u = 6 ÷ 6 = 1
Substitute 1 u = 1 into (1).
2 u + 8 p = 82
2 x 1 + 8 p = 82
2 + 8 p = 82
8 p = 82 - 2 = 80
1 p = 80 ÷ 8 = 10
Amount that Bryan has at first
= 2 u
= 2 x 1
= $2
(b)
Amount that Adam has in the end
= 8 p - 1 p
= 7 p
= 7 x 10
= $70
Answer(s): (a) $2; (b) $70