Nora and Sarah have some money. If Nora spends $11, she will have
25 as much money as Sarah. If Sarah spends $18, Nora will have
56 as much money as Sarah. How much money does Nora have?
| |
Case 1 |
Case 2 |
| |
Nora |
Sarah |
Nora |
Sarah |
| Before |
2 u + $11 |
5 u |
5 p |
6 p + $18 |
| Change |
- $11 |
|
|
- $18 |
| After |
2 u |
5 u |
5 p |
6 p |
The amount that Nora 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 Sarah has at first in Case 1 and Case 2 is the same.
5 u = 6 p + 18 --- (2)
Make u the same.
(1)
x 510 u = 25 p - 55 --- (3)
(2)
x 210 u = 12 p + 36 --- (4)
(3) = (4)
25 p - 55 = 12 p + 36
25 p - 12 p = 55 + 36
13 p = 91
1 p = 91 ÷ 13 = 7
Amount that Nora has
= 5 p
= 5 x 7
= $35
Answer(s): $35
