Lee had 6 times as many cards as George at first. Then each of them bought an equal number of new cards. In the end, George had 50 cards and Lee had 5 times as many cards as George. How many cards did both of them buy altogether?
| |
Lee |
George |
Difference |
| Before |
6x4 =
24 u |
1x4 =
4 u |
5x4 =
20 u |
| Change |
+ ? |
+ ? |
|
| After |
5x5 =
25 u |
1x5 =
5 u |
4x5 =
20 u |
The difference in the number of cards at first and in the end remains unchanged. Make the difference in the number of cards at first and in the end the same. LCM of 5 and 4 is 20.
Number of cards that George had in the end = 5 u
5 u = 50
1 u = 50 ÷ 5 = 10
Number of cards that Lee bought
= 25 u - 24 u
= 1 u
Number of cards that both of them bought altogether
= 2 x 1 u
= 2 u
= 2 x 10
= 20
Answer(s): 20
