Bryan and Adam have a total of $125.
Bryan spends
15 of his money and
Adam spends
18 of his money.
They spend $16 altogether.
- How much does Bryan have at first?
- How much does Adam have in the end?
|
Bryan |
Adam |
Before |
5 u |
8 p |
Change |
- 1 u |
- 1 p |
After |
4 u |
7 p |
(a)
Amount that Bryan has at first = 5 u
Amount that Adam has at first = 8 p
Total amount that they have = 5 u + 8 p = 125 --- (1)
Total amount that they spend = 1 u + 1 p = 16 --- (2)
(2)
x 8 8 u + 8 p = 128 --- (3)
(3) - (1)
(8 u + 8 p) - (5 u + 8 p) = 128 - 125
8 u + 8 p - 5 u - 8 p = 128 - 125
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 = 125
5 x 1 + 8 p = 125
5 + 8 p = 125
8 p = 125 - 5 = 120
1 p = 120 ÷ 8 = 15
Amount that Bryan has at first
= 5 u
= 5 x 1
= $5
(b)
Amount that Adam has in the end
= 8 p - 1 p
= 7 p
= 7 x 15
= $105
Answer(s): (a) $5; (b) $105