Bryan and Adam have a total of $240.
Bryan spends
13 of his money and
Adam spends
18 of his money.
They spend $45 altogether.
- How much does Bryan have at first?
- How much does Adam have in the end?
|
Bryan |
Adam |
Before |
3 u |
8 p |
Change |
- 1 u |
- 1 p |
After |
2 u |
7 p |
(a)
Amount that Bryan has at first = 3 u
Amount that Adam has at first = 8 p
Total amount that they have = 3 u + 8 p = 240 --- (1)
Total amount that they spend = 1 u + 1 p = 45 --- (2)
(2)
x 8 8 u + 8 p = 360 --- (3)
(3) - (1)
(8 u + 8 p) - (3 u + 8 p) = 360 - 240
8 u + 8 p - 3 u - 8 p = 360 - 240
8 u - 3 u + 8 p - 8 p = 120
8 u - 3 u = 120
5 u = 120
1 u = 120 ÷ 5 = 24
Substitute 1 u = 24 into (1).
3 u + 8 p = 240
3 x 24 + 8 p = 240
72 + 8 p = 240
8 p = 240 - 72 = 168
1 p = 168 ÷ 8 = 21
Amount that Bryan has at first
= 3 u
= 3 x 24
= $72
(b)
Amount that Adam has in the end
= 8 p - 1 p
= 7 p
= 7 x 21
= $147
Answer(s): (a) $72; (b) $147