Last week, Ryan had a total of 180 red and grey pencils. Two weeks later, he sold
34 of all the red pencils and bought another 10 grey pencils. Now he has the same number of red and grey pencils. How many pencils does he have in the end?
| |
Red |
Grey |
Total |
| Before |
4 u |
1 u - 10 |
5 u - 10 |
| Change |
- 3 u |
+ 10 |
|
| After |
1 u |
1 u |
|
Comparing the red
and grey pencils in the end |
1 |
1 |
|
Total number of pencils at first
= 4 u + 1 u - 10
= 5 u - 10
5 u - 10 = 180
5 u = 180 + 10
5 u = 190
1 u = 190 ÷ 5 = 38
Number of pencils that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 38
= 76
Answer(s): 76
