There was an equal number of girls and boys at the computer lab. After
25 of the girls and 52 boys left the computer lab, there were 20 more girls than boys at the computer lab. How many students were there at the computer lab at first?
| |
Girls |
Boys |
| Before |
5 u |
5 u |
| Change |
- 2 u |
- 52 |
| After |
3 u |
5 u - 52 |
Number of girls in the end
= 5 u - 2 u
= 3 u
If another 20 boys entered the computer lab, the number of girls and boys would be the same.
5 u - 52 + 20 = 3 u
5 u - 32 = 3 u
5 u - 3 u = 32
2 u = 32
1 u = 32 ÷ 2 = 16
Number of students in the computer lab at first
= 10 u
= 10 x 16
= 160
Answer(s): 160
