Barbara and Jen have some money. If Barbara spends $17, she will have
25 as much money as Jen. If Jen spends $7, Barbara will have
57 as much money as Jen. How much money does Barbara have?
| |
Case 1 |
Case 2 |
| |
Barbara |
Jen |
Barbara |
Jen |
| Before |
2 u + $17 |
5 u |
5 p |
7 p + $7 |
| Change |
- $17 |
|
|
- $7 |
| After |
2 u |
5 u |
5 p |
7 p |
The amount that Barbara has at first in Case 1 and Case 2 is the same.
2 u + 17 = 5 p
2 u = 5 p - 17 --- (1)
The amount that Jen has at first in Case 1 and Case 2 is the same.
5 u = 7 p + 7 --- (2)
Make u the same.
(1)
x 510 u = 25 p - 85 --- (3)
(2)
x 210 u = 14 p + 14 --- (4)
(3) = (4)
25 p - 85 = 14 p + 14
25 p - 14 p = 85 + 14
11 p = 99
1 p = 99 ÷ 11 = 9
Amount that Barbara has
= 5 p
= 5 x 9
= $45
Answer(s): $45
