Mark and Opal shared some pens equally. After Opal bought 39 pens and Mark gave 147 pens away, they had 158 pens left. How many pens did each of them have at first?
| |
Mark |
Opal |
Total |
| Before |
1 u |
1 u |
|
| Change |
+ 39 |
- 147 |
|
| After |
1 u + 39 |
1 u - 147 |
158 |
Mark and Opal had the same number of pens at first.
Total number of pens in the end
= 1 u + 39 + 1 u - 147
= 1 u + 1 u + 39 - 147
= 2 u - 108
2 u - 108 = 158
2 u = 158 + 108
2 u = 266
1 u = 266 ÷ 2 = 133
Number of pens that each of them had at first
= 1 u
= 133
Answer(s): 133
