If Boys pass % - 62 girls pass% - 76 overall pass percentage of class % - 68 Find what percentage of Students in class were Girls?

Let b total number of boys, g total number of girls

given 0.62b+0.76g=0.68(b+g)

solve this you will get b:g=4:3

find % of girls students easily from this.

let x percent be boys and y percent be girls. The given 68 % is the weighted average of boys and girls pass %. so 62x+76y/x+y=68. and x+y=100. solve these two equations to get values for x and y.