Cathy and Tammy have some money. If Cathy spends $4, she will have
25 as much money as Tammy. If Tammy spends $3, Cathy will have
56 as much money as Tammy. How much money does Tammy have?
| |
Case 1 |
Case 2 |
| |
Cathy |
Tammy |
Cathy |
Tammy |
| Before |
2 u + $4 |
5 u |
5 p |
6 p + $3 |
| Change |
- $4 |
|
|
- $3 |
| After |
2 u |
5 u |
5 p |
6 p |
The amount that Cathy has at first in Case 1 and Case 2 is the same.
2 u + 4 = 5 p
2 u = 5 p - 4 --- (1)
The amount that Tammy has at first in Case 1 and Case 2 is the same.
5 u = 6 p + 3 --- (2)
Make u the same.
(1)
x 510 u = 25 p - 20 --- (3)
(2)
x 210 u = 12 p + 6 --- (4)
(3) = (4)
25 p - 20 = 12 p + 6
25 p - 12 p = 20 + 6
13 p = 26
1 p = 26 ÷ 13 = 2
Amount that Tammy has
= 6 p + 3
= 6 x 2 + 3
= 12 + 3
= $15
Answer(s): $15
