Last week, Zeph had a total of 199 purple and black pens. Two weeks later, he sold
23 of all the purple pens and 11 black pens. Now he has the same number of purple and black pens. How many pens does he have in the end?
| |
Purple |
Black |
Total |
| Before |
3 u |
1 u + 11 |
4 u + 11 |
| Change |
- 2 u |
- 11 |
|
| After |
1 u |
1 u |
|
Comparing the purple
and black pens in the end |
1 |
1 |
|
Total number of pens at first
= 3 u + 1 u + 11
= 4 u + 11
4 u + 11 = 199
4 u = 199 - 11
4 u = 188
1 u = 188 ÷ 4 = 47
Number of pens that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 47
= 94
Answer(s): 94
