At first, Ivan had 21 chocolate bars and Seth had 6 times as many chocolate bars as Ivan. After they each received an equal number of chocolate bars from their cousin, Seth had four times as many chocolate bars as Ivan. How many chocolate bars did their cousin give to both of them altogether?
| |
Ivan |
Seth |
Difference |
| Before |
1x3 =
3 u |
6x3 =
18 u |
5x3 =
15 u |
| Change |
+ 2 u |
+ 2 u |
|
| After |
1x5 =
5 u |
4x5 =
20 u |
3x5 =
15 u |
Since both received an equal number of chocolate bars, the difference in the number of chocolate bars remains unchanged. LCM of 5 and 3 is 15.
3 u = 21
1 u = 21 ÷ 3 = 7
Number of chocolate bars that each received
= 5 u - 3 u
= 2 u
Number of chocolate bars that both of them received altogether
= 2 x 2 u
= 4 u
= 4 x 7
= 28
Answer(s): 28
