Eric and Dylan had 63 files. After Eric gave 12 files to Dylan. Dylan, in return, gave half of his files to Eric. In the end, Eric had twice as many files as Dylan. How many files did Eric have at first?
| |
Eric |
Dylan |
Total |
| Before |
1 u + 12 |
2 u - 12 |
63 |
| Change 1 |
- 12 |
+ 12 |
|
| After 1 |
1 u |
2 u |
|
| Change 2 |
+ 1 u |
- 1 u |
|
| After 2 |
2 u |
1 u |
63 |
Total number of files that Eric and Dylan had at first and in the end remains unchanged.
Total number of files
= 2 u + 1 u
= 3 u
1 u = 63 ÷ 3 = 21
Number of files that Eric had at first
= 1 u + 12
= 21 + 12
= 33
Answer(s): 33
