Ben and Sean had 90 pens. After Ben gave 16 pens to Sean. Sean, in return, gave half of his pens to Ben. In the end, Ben had twice as many pens as Sean. How many pens did Ben have at first?
| |
Ben |
Sean |
Total |
| Before |
1 u + 16 |
2 u - 16 |
90 |
| Change 1 |
- 16 |
+ 16 |
|
| After 1 |
1 u |
2 u |
|
| Change 2 |
+ 1 u |
- 1 u |
|
| After 2 |
2 u |
1 u |
90 |
Total number of pens that Ben and Sean had at first and in the end remains unchanged.
Total number of pens
= 2 u + 1 u
= 3 u
1 u = 90 ÷ 3 = 30
Number of pens that Ben had at first
= 1 u + 16
= 30 + 16
= 46
Answer(s): 46
