Sam had 5 times as many marbles as Pierre at first. Then each of them bought an equal number of new marbles. In the end, Pierre had 16 marbles and Sam had 4 times as many marbles as Pierre. How many marbles did both of them buy altogether?
| |
Sam |
Pierre |
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 marbles at first and in the end remains unchanged. Make the difference in the number of marbles at first and in the end the same. LCM of 4 and 3 is 12.
Number of marbles that Pierre had in the end = 4 u
4 u = 16
1 u = 16 ÷ 4 = 4
Number of marbles that Sam bought
= 16 u - 15 u
= 1 u
Number of marbles that both of them bought altogether
= 2 x 1 u
= 2 u
= 2 x 4
= 8
Answer(s): 8
