Last week, Bobby had a total of 339 yellow and red pens. Two weeks later, he sold
45 of all the yellow pens and 21 red pens. Now he has the same number of yellow and red pens. How many pens does he have in the end?
| |
Yellow |
Red |
Total |
| Before |
5 u |
1 u + 21 |
6 u + 21 |
| Change |
- 4 u |
- 21 |
|
| After |
1 u |
1 u |
|
Comparing the yellow
and red pens in the end |
1 |
1 |
|
Total number of pens at first
= 5 u + 1 u + 21
= 6 u + 21
6 u + 21 = 339
6 u = 339 - 21
6 u = 318
1 u = 318 ÷ 6 = 53
Number of pens that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 53
= 106
Answer(s): 106
