there are 342 boys and girls at the canteen. after 51 boys and an equal number of girls as boys returned to their classroom, there were three times the number of boys than girls in the canteen. How many boys were there in the canteen at first?
There were 240 kids left at the canteen, after 102(total)people left. 240/4 = 60. 180 boys and 60 girls were left. 180 is 3 times as many of 60(girls).
