Last week, Tom had a total of 73 blue and green pens. Two weeks later, he sold
23 of all the blue pens and bought another 15 green pens. Now he has the same number of blue and green pens. How many pens does he have in the end?
| |
Blue |
Green |
Total |
| Before |
3 u |
1 u - 15 |
4 u - 15 |
| Change |
- 2 u |
+ 15 |
|
| After |
1 u |
1 u |
|
Comparing the blue
and green pens in the end |
1 |
1 |
|
Total number of pens at first
= 3 u + 1 u - 15
= 4 u - 15
4 u - 15 = 73
4 u = 73 + 15
4 u = 88
1 u = 88 ÷ 4 = 22
Number of pens that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 22
= 44
Answer(s): 44
