Adam and Bryan have a total of $42.
Adam spends
12 of his money and
Bryan spends
14 of his money.
They spend $15 altogether.
- How much does Adam have at first?
- How much does Bryan have in the end?
|
Adam |
Bryan |
Before |
2 u |
4 p |
Change |
- 1 u |
- 1 p |
After |
1 u |
3 p |
(a)
Amount that Adam has at first = 2 u
Amount that Bryan has at first = 4 p
Total amount that they have = 2 u + 4 p = 42 --- (1)
Total amount that they spend = 1 u + 1 p = 15 --- (2)
(2)
x 4 4 u + 4 p = 60 --- (3)
(3) - (1)
(4 u + 4 p) - (2 u + 4 p) = 60 - 42
4 u + 4 p - 2 u - 4 p = 60 - 42
4 u - 2 u + 4 p - 4 p = 18
4 u - 2 u = 18
2 u = 18
1 u = 18 ÷ 2 = 9
Substitute 1 u = 9 into (1).
2 u + 4 p = 42
2 x 9 + 4 p = 42
18 + 4 p = 42
4 p = 42 - 18 = 24
1 p = 24 ÷ 4 = 6
Amount that Adam has at first
= 2 u
= 2 x 9
= $18
(b)
Amount that Bryan has in the end
= 4 p - 1 p
= 3 p
= 3 x 6
= $18
Answer(s): (a) $18; (b) $18