Zara and Kylie have some money. If Zara spends $12, she will have
25 as much money as Kylie. If Kylie spends $9, Zara will have
56 as much money as Kylie. How much money does Kylie have?
| |
Case 1 |
Case 2 |
| |
Zara |
Kylie |
Zara |
Kylie |
| Before |
2 u + $12 |
5 u |
5 p |
6 p + $9 |
| Change |
- $12 |
|
|
- $9 |
| After |
2 u |
5 u |
5 p |
6 p |
The amount that Zara has at first in Case 1 and Case 2 is the same.
2 u + 12 = 5 p
2 u = 5 p - 12 --- (1)
The amount that Kylie has at first in Case 1 and Case 2 is the same.
5 u = 6 p + 9 --- (2)
Make u the same.
(1)
x 510 u = 25 p - 60 --- (3)
(2)
x 210 u = 12 p + 18 --- (4)
(3) = (4)
25 p - 60 = 12 p + 18
25 p - 12 p = 60 + 18
13 p = 78
1 p = 78 ÷ 13 = 6
Amount that Kylie has
= 6 p + 9
= 6 x 6 + 9
= 36 + 9
= $45
Answer(s): $45
