Ethan and Xavier had 81 pens. After Ethan gave 12 pens to Xavier. Xavier, in return, gave half of his pens to Ethan. In the end, Ethan had twice as many pens as Xavier. How many pens did Ethan have at first?
| |
Ethan |
Xavier |
Total |
| Before |
1 u + 12 |
2 u - 12 |
81 |
| Change 1 |
- 12 |
+ 12 |
|
| After 1 |
1 u |
2 u |
|
| Change 2 |
+ 1 u |
- 1 u |
|
| After 2 |
2 u |
1 u |
81 |
Total number of pens that Ethan and Xavier had at first and in the end remains unchanged.
Total number of pens
= 2 u + 1 u
= 3 u
1 u = 81 ÷ 3 = 27
Number of pens that Ethan had at first
= 1 u + 12
= 27 + 12
= 39
Answer(s): 39
