The number of boys in the school hall was
25 that of the girls. There were 150 more girls than boys. After some girls had left the school hall, the number of boys at the school hall was twice the number of the remaining girls. How many girls left the school hall?
| |
Girls |
Boys |
Difference |
| Before |
5 u |
2 u |
3 u |
| Change |
- ? |
|
|
| After |
1 u |
2 u |
|
The number of boys at first and in the end remains unchanged.
Number of more girls than boys at first
= 5 u - 2 u
= 3 u
3 u = 150
1 u = 150 ÷ 3 = 50
Number of girls that left
= 5 u - 1 u
= 4 u
= 4 x 50
= 200
Answer(s): 200
