Last week, Julian had a total of 155 purple and white pens. Two weeks later, he sold
23 of all the purple pens and bought another 25 white pens. Now he has the same number of purple and white pens. How many pens does he have in the end?
| |
Purple |
White |
Total |
| Before |
3 u |
1 u - 25 |
4 u - 25 |
| Change |
- 2 u |
+ 25 |
|
| After |
1 u |
1 u |
|
Comparing the purple
and white pens in the end |
1 |
1 |
|
Total number of pens at first
= 3 u + 1 u - 25
= 4 u - 25
4 u - 25 = 155
4 u = 155 + 25
4 u = 180
1 u = 180 ÷ 4 = 45
Number of pens that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 45
= 90
Answer(s): 90
