If Billy gives Min $9, he will have the same amount of money as her. If Min gives Billy $9, Billy will have four times as much money as her. How much money does Min have?
| |
Scenario 1 |
Scenario 2 |
| |
Billy |
Min |
Total |
Billy |
Min |
Total |
| Before |
5 u + 9 |
5 u - 9 |
|
2 u - 9 |
8 u + 9 |
|
| Change |
- 9 |
+ 9 |
|
+ 9 |
- 9 |
|
| After |
1x5 =
5 u |
1x5 =
5 u |
2x5 =
10 u |
1x2 =
2 u |
4x2 =
8 u |
5x2 =
10 u |
The total amount in both scenarios is the same. LCM of 2 and 5 is 10.
In both scenarios, Billy had the same amount at first.
5 u + 9 = 2 u - 9
5 u - 2 u = 9 + 9
3 u = 18
1 u = 18 ÷ 3 = 6
Amount that Min has
= 5 u - 9
= 5 x 6 - 9
= $21
Answer(s): $21
