Luis had $110 less than Billy. If Billy spends $80 and Luis's mother gave Luis $970, Billy will have
15 as much money as Luis. How much money did Luis and Billy have?
| |
Make p the same
(1)x5 = (3) |
Luis
(1) |
Billy
(2) |
| Before |
5 u |
1 u |
1 u + 110 |
| Change |
- 400 |
- 80 |
+ 970 |
| After |
5 p |
1 p |
5 p |
Since Luis had $110 less than Billy, this means Billy had $110 more than Luis.
1 u - 80 = 1 p --- (1)
1 u + 110 + 970 = 5 p
1 u + 1080 =
5 p --- (2)
Make p the same.
(1)
x5
5 u - 400 =
5 p --- (3)
(3) = (2)
5 u - 400 = 1 u + 1080
5 u - 1 u = 1080 + 400
4 u = 1480
1 u = 1480 ÷ 4 = 370
Total amount that Luis and Billy had
= 1 u + 1 u + 110
= 2 u + 110
= 2 x 370 + 110
= 740 + 110
= $850
Answer(s): $850
