Peter had $160 less than Justin. If Justin spends $70 and Peter's mother gave Peter $70, Justin will have
13 as much money as Peter. How much money did Peter and Justin have?
| |
Make p the same
(1)x3 = (3) |
Peter
(1) |
Justin
(2) |
| Before |
3 u |
1 u |
1 u + 160 |
| Change |
- 210 |
- 70 |
+ 70 |
| After |
3 p |
1 p |
3 p |
Since Peter had $160 less than Justin, this means Justin had $160 more than Peter.
1 u - 70 = 1 p --- (1)
1 u + 160 + 70 = 3 p
1 u + 230 =
3 p --- (2)
Make p the same.
(1)
x3
3 u - 210 =
3 p --- (3)
(3) = (2)
3 u - 210 = 1 u + 230
3 u - 1 u = 230 + 210
2 u = 440
1 u = 440 ÷ 2 = 220
Total amount that Peter and Justin had
= 1 u + 1 u + 160
= 2 u + 160
= 2 x 220 + 160
= 440 + 160
= $600
Answer(s): $600
