60% of the students in class are girls. If there are 15 girls, how many students are in class? 59

I'm terrible at math any here is appreciated.

1. what are the missing reasons in the proof 2. it's in the second picture and 3

The la dodgers hit the most homeruns in 2014. the number of homeruns accounted for 6% of the entire major leauge baseball homerun count. if 583 total homeruns were hit, approximately how many did the la dodgers hit