John had $170 less than Peter. If Peter spends $200 and John's mother gave John $10, Peter will have
13 as much money as John. How much money did John and Peter have?
| |
Make p the same
(1)x3 = (3) |
John
(1) |
Peter
(2) |
| Before |
3 u |
1 u |
1 u + 170 |
| Change |
- 600 |
- 200 |
+ 10 |
| After |
3 p |
1 p |
3 p |
Since John had $170 less than Peter, this means Peter had $170 more than John.
1 u - 200 = 1 p --- (1)
1 u + 170 + 10 = 3 p
1 u + 180 =
3 p --- (2)
Make p the same.
(1)
x3
3 u - 600 =
3 p --- (3)
(3) = (2)
3 u - 600 = 1 u + 180
3 u - 1 u = 180 + 600
2 u = 780
1 u = 780 ÷ 2 = 390
Total amount that John and Peter had
= 1 u + 1 u + 170
= 2 u + 170
= 2 x 390 + 170
= 780 + 170
= $950
Answer(s): $950
