Bryan and Adam have a total of $149.
Bryan spends
12 of his money and
Adam spends
17 of his money.
They spend $42 altogether.
- How much does Bryan have at first?
- How much does Adam have in the end?
|
Bryan |
Adam |
Before |
2 u |
7 p |
Change |
- 1 u |
- 1 p |
After |
1 u |
6 p |
(a)
Amount that Bryan has at first = 2 u
Amount that Adam has at first = 7 p
Total amount that they have = 2 u + 7 p = 149 --- (1)
Total amount that they spend = 1 u + 1 p = 42 --- (2)
(2)
x 7 7 u + 7 p = 294 --- (3)
(3) - (1)
(7 u + 7 p) - (2 u + 7 p) = 294 - 149
7 u + 7 p - 2 u - 7 p = 294 - 149
7 u - 2 u + 7 p - 7 p = 145
7 u - 2 u = 145
5 u = 145
1 u = 145 ÷ 5 = 29
Substitute 1 u = 29 into (1).
2 u + 7 p = 149
2 x 29 + 7 p = 149
58 + 7 p = 149
7 p = 149 - 58 = 91
1 p = 91 ÷ 7 = 13
Amount that Bryan has at first
= 2 u
= 2 x 29
= $58
(b)
Amount that Adam has in the end
= 7 p - 1 p
= 6 p
= 6 x 13
= $78
Answer(s): (a) $58; (b) $78