Last week, Sam had a total of 138 blue and white pencils. Two weeks later, he sold
45 of all the blue pencils and 12 white pencils. Now he has the same number of blue and white pencils. How many pencils does he have in the end?
| |
Blue |
White |
Total |
| Before |
5 u |
1 u + 12 |
6 u + 12 |
| Change |
- 4 u |
- 12 |
|
| After |
1 u |
1 u |
|
Comparing the blue
and white pencils in the end |
1 |
1 |
|
Total number of pencils at first
= 5 u + 1 u + 12
= 6 u + 12
6 u + 12 = 138
6 u = 138 - 12
6 u = 126
1 u = 126 ÷ 6 = 21
Number of pencils that he has in the end
= 1 u + 1 u
= 2 u
= 2 x 21
= 42
Answer(s): 42
