Paul and Ivan had 54 notebooks. After Paul gave 13 notebooks to Ivan. Ivan, in return, gave half of his notebooks to Paul. In the end, Paul had twice as many notebooks as Ivan. How many notebooks did Paul have at first?
| |
Paul |
Ivan |
Total |
| Before |
1 u + 13 |
2 u - 13 |
54 |
| Change 1 |
- 13 |
+ 13 |
|
| After 1 |
1 u |
2 u |
|
| Change 2 |
+ 1 u |
- 1 u |
|
| After 2 |
2 u |
1 u |
54 |
Total number of notebooks that Paul and Ivan had at first and in the end remains unchanged.
Total number of notebooks
= 2 u + 1 u
= 3 u
1 u = 54 ÷ 3 = 18
Number of notebooks that Paul had at first
= 1 u + 13
= 18 + 13
= 31
Answer(s): 31
