Winnie and Zoe have some money. If Winnie spends $7, she will have
25 as much money as Zoe. If Zoe spends $5, Winnie will have
58 as much money as Zoe. How much money does Winnie have?
| |
Case 1 |
Case 2 |
| |
Winnie |
Zoe |
Winnie |
Zoe |
| Before |
2 u + $7 |
5 u |
5 p |
8 p + $5 |
| Change |
- $7 |
|
|
- $5 |
| After |
2 u |
5 u |
5 p |
8 p |
The amount that Winnie has at first in Case 1 and Case 2 is the same.
2 u + 7 = 5 p
2 u = 5 p - 7 --- (1)
The amount that Zoe has at first in Case 1 and Case 2 is the same.
5 u = 8 p + 5 --- (2)
Make u the same.
(1)
x 510 u = 25 p - 35 --- (3)
(2)
x 210 u = 16 p + 10 --- (4)
(3) = (4)
25 p - 35 = 16 p + 10
25 p - 16 p = 35 + 10
9 p = 45
1 p = 45 ÷ 9 = 5
Amount that Winnie has
= 5 p
= 5 x 5
= $25
Answer(s): $25
