Opal and Shiyun have some money. If Opal spends $11, she will have
25 as much money as Shiyun. If Shiyun spends $4, Opal will have
58 as much money as Shiyun. How much money does Opal have?
| |
Case 1 |
Case 2 |
| |
Opal |
Shiyun |
Opal |
Shiyun |
| Before |
2 u + $11 |
5 u |
5 p |
8 p + $4 |
| Change |
- $11 |
|
|
- $4 |
| After |
2 u |
5 u |
5 p |
8 p |
The amount that Opal has at first in Case 1 and Case 2 is the same.
2 u + 11 = 5 p
2 u = 5 p - 11 --- (1)
The amount that Shiyun has at first in Case 1 and Case 2 is the same.
5 u = 8 p + 4 --- (2)
Make u the same.
(1)
x 510 u = 25 p - 55 --- (3)
(2)
x 210 u = 16 p + 8 --- (4)
(3) = (4)
25 p - 55 = 16 p + 8
25 p - 16 p = 55 + 8
9 p = 63
1 p = 63 ÷ 9 = 7
Amount that Opal has
= 5 p
= 5 x 7
= $35
Answer(s): $35
