There was an equal number of boys and girls at the computer lab. After
79 of the boys and 60 girls left the computer lab, there were 18 more boys than girls at the computer lab. How many students were there at the computer lab at first?
|
Boys |
Girls |
Before |
9 u |
9 u |
Change |
- 7 u |
- 60 |
After |
2 u |
9 u - 60 |
Number of boys in the end
= 9 u - 7 u
= 2 u
If another 18 girls entered the computer lab, the number of boys and girls would be the same.
9 u - 60 + 18 = 2 u
9 u - 42 = 2 u
9 u - 2 u = 42
7 u = 42
1 u = 42 ÷ 7 = 6
Number of students in the computer lab at first
= 18 u
= 18 x 6
= 108
Answer(s): 108