Adam and Bryan have a total of $77.
Adam spends
13 of his money and
Bryan spends
15 of his money.
They spend $19 altogether.
- How much does Adam have at first?
- How much does Bryan have in the end?
|
Adam |
Bryan |
Before |
3 u |
5 p |
Change |
- 1 u |
- 1 p |
After |
2 u |
4 p |
(a)
Amount that Adam has at first = 3 u
Amount that Bryan has at first = 5 p
Total amount that they have = 3 u + 5 p = 77 --- (1)
Total amount that they spend = 1 u + 1 p = 19 --- (2)
(2)
x 5 5 u + 5 p = 95 --- (3)
(3) - (1)
(5 u + 5 p) - (3 u + 5 p) = 95 - 77
5 u + 5 p - 3 u - 5 p = 95 - 77
5 u - 3 u + 5 p - 5 p = 18
5 u - 3 u = 18
2 u = 18
1 u = 18 ÷ 2 = 9
Substitute 1 u = 9 into (1).
3 u + 5 p = 77
3 x 9 + 5 p = 77
27 + 5 p = 77
5 p = 77 - 27 = 50
1 p = 50 ÷ 5 = 10
Amount that Adam has at first
= 3 u
= 3 x 9
= $27
(b)
Amount that Bryan has in the end
= 5 p - 1 p
= 4 p
= 4 x 10
= $40
Answer(s): (a) $27; (b) $40