At first, Oliver had 21 mini cupcakes and Tom had 6 times as many mini cupcakes as Oliver. After they each received an equal number of mini cupcakes from their neighbour, Tom had four times as many mini cupcakes as Oliver. How many mini cupcakes did their neighbour give to both of them altogether?
| |
Oliver |
Tom |
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 mini cupcakes, the difference in the number of mini cupcakes remains unchanged. LCM of 5 and 3 is 15.
3 u = 21
1 u = 21 ÷ 3 = 7
Number of mini cupcakes that each received
= 5 u - 3 u
= 2 u
Number of mini cupcakes that both of them received altogether
= 2 x 2 u
= 4 u
= 4 x 7
= 28
Answer(s): 28
