Nick had 4 times as many erasers as Perry at first. Then each of them bought an equal number of new erasers. In the end, Perry had 15 erasers and Nick had 3 times as many erasers as Perry. How many erasers did both of them buy altogether?
| |
Nick |
Perry |
Difference |
| Before |
4x2 =
8 u |
1x2 =
2 u |
3x2 =
6 u |
| Change |
+ ? |
+ ? |
|
| After |
3x3 =
9 u |
1x3 =
3 u |
2x3 =
6 u |
The difference in the number of erasers at first and in the end remains unchanged. Make the difference in the number of erasers at first and in the end the same. LCM of 3 and 2 is 6.
Number of erasers that Perry had in the end = 3 u
3 u = 15
1 u = 15 ÷ 3 = 5
Number of erasers that Nick bought
= 9 u - 8 u
= 1 u
Number of erasers that both of them bought altogether
= 2 x 1 u
= 2 u
= 2 x 5
= 10
Answer(s): 10
