We have a 900 students. We will divide 900 by 3 because the 3 mainly showes all the students. 900 divided by 3 is 300. So we have 3 groups of 300 students. Now there are 2 groups of girls and 1 group of boys. 300/900= 33% but we have 600. I hope you kind of understand but the answer is 66% of girls. (34% are boys)
