John and Sean went shopping with a total amount of $280. They had $240 left after shopping. John's remaining money was 5 times the amount he paid for. Sean's remaining money was 7 times the amount he had spent.
- How much did Sean spend?
- How much did Sean bring along for shopping?
| |
John |
Sean |
Total |
| Before |
6 u |
8 p |
280 |
| Change |
- 1 u |
- 1 p |
- 40 |
| After |
5 u |
7 p |
240 |
(a)
Amount that John and Sean spent
= 280 - 240
= $40
Amount that John and Sean spent
= 1 u + 1 p
1 u + 1 p = 40
1 u = 40 - 1 p --- (1)
Amount that John and Sean had left
= 5 u + 7 p
5 u + 7 p = 240
5 u = 240 - 7 p --- (2)
Make u the same.
(1)
x 5 5 u = 200 - 5 p --- (3)
(3) = (2)
200 - 5 p = 240 - 7 p
7 p - 5 p = 240 - 200
2 p = 40
1 p = 40 ÷ 2 = 20
Amount that Sean spent = $20
(b)
Amount that Sean brought along
= 8 p
= 8 x 20
= $160
Answer(s): (a) $20; (b) $160
