Mark and Tommy had 87 pencils. After Mark gave 15 pencils to Tommy. Tommy, in return, gave half of his pencils to Mark. In the end, Mark had twice as many pencils as Tommy. How many pencils did Mark have at first?
| |
Mark |
Tommy |
Total |
| Before |
1 u + 15 |
2 u - 15 |
87 |
| Change 1 |
- 15 |
+ 15 |
|
| After 1 |
1 u |
2 u |
|
| Change 2 |
+ 1 u |
- 1 u |
|
| After 2 |
2 u |
1 u |
87 |
Total number of pencils that Mark and Tommy had at first and in the end remains unchanged.
Total number of pencils
= 2 u + 1 u
= 3 u
1 u = 87 ÷ 3 = 29
Number of pencils that Mark had at first
= 1 u + 15
= 29 + 15
= 44
Answer(s): 44
