Justin had 5 times as many beads as Charlie at first. Then each of them bought an equal number of new beads. In the end, Charlie had 40 beads and Justin had 4 times as many beads as Charlie. How many beads did both of them buy altogether?
| |
Justin |
Charlie |
Difference |
| Before |
5x3 =
15 u |
1x3 =
3 u |
4x3 =
12 u |
| Change |
+ ? |
+ ? |
|
| After |
4x4 =
16 u |
1x4 =
4 u |
3x4 =
12 u |
The difference in the number of beads at first and in the end remains unchanged. Make the difference in the number of beads at first and in the end the same. LCM of 4 and 3 is 12.
Number of beads that Charlie had in the end = 4 u
4 u = 40
1 u = 40 ÷ 4 = 10
Number of beads that Justin bought
= 16 u - 15 u
= 1 u
Number of beads that both of them bought altogether
= 2 x 1 u
= 2 u
= 2 x 10
= 20
Answer(s): 20
