Charlie had 6 times as many stamps as Lee at first. Then each of them bought an equal number of new stamps. In the end, Lee had 45 stamps and Charlie had 3 times as many stamps as Lee. How many stamps did both of them buy altogether?
| |
Charlie |
Lee |
Difference |
| Before |
6x2 =
12 u |
1x2 =
2 u |
5x2 =
10 u |
| Change |
+ ? |
+ ? |
|
| After |
3x5 =
15 u |
1x5 =
5 u |
2x5 =
10 u |
The difference in the number of stamps at first and in the end remains unchanged. Make the difference in the number of stamps at first and in the end the same. LCM of 5 and 2 is 10.
Number of stamps that Lee had in the end = 5 u
5 u = 45
1 u = 45 ÷ 5 = 9
Number of stamps that Charlie bought
= 15 u - 12 u
= 3 u
Number of stamps that both of them bought altogether
= 2 x 3 u
= 6 u
= 6 x 9
= 54
Answer(s): 54
