The number of girls in the lecture hall was
35 that of the boys. There were 154 more boys than girls. After some boys had left the lecture hall, the number of girls at the lecture hall was thrice the number of the remaining boys. How many boys left the lecture hall?
| |
Boys |
Girls |
Difference |
| Before |
5 u |
3 u |
2 u |
| Change |
- ? |
|
|
| After |
1 u |
3 u |
|
The number of girls at first and in the end remains unchanged.
Number of more boys than girls at first
= 5 u - 3 u
= 2 u
2 u = 154
1 u = 154 ÷ 2 = 77
Number of boys that left
= 5 u - 1 u
= 4 u
= 4 x 77
= 308
Answer(s): 308
