If David gives Usha $9, he will have the same amount of money as her. If Usha gives David $9, David will have five times as much money as her. How much money does David have?
| |
Case 1 |
Case 2 |
| |
David |
Usha |
David |
Usha |
| Before |
3 u + 9 |
3 u - 9 |
1 u - 9 |
5 u + 9 |
| Change |
- 9 |
+ 9 |
+ 9 |
- 9 |
| After |
1x3 =
3 u |
1x3 =
3 u |
1x1 =
1 u |
5x1 =
5 u |
The total amount in both scenarios is the same. Make the total amount the same in bothe cases. LCM of 2 and 6 is 6.
In both case, David had the same amount at first.
3 u + 9 = 1 u - 9
3 u - 1 u = 9 + 9
2 u = 18
1 u = 18 ÷ 2 = 9
Amount that David has
= 3 u + 9
= 3 x 9 + 9
= $36
Answer(s): $36
