Question
The number of girls in the lecture hall was 57 that of the boys. There were 104 more boys than girls. After some boys had left the lecture hall, the number of girls at the lecture hall was five times the number of the remaining boys. How many boys left the lecture hall?
4 m

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The number of girls in the lecture hall was 57 that of the boys. There were 104 more boys than girls. After some boys had left the lecture hall, the number of girls at the lecture hall was five times the number of the remaining boys. How many boys left the lecture hall?