If
of the class is girls, and
of the girls in the class are wearing dresses, what fraction of the class are girls with dresses?
Let's say there are 100 students in the class.
If 60% of the class is girls, that means there are 60 girls in the class.
If 80% of the girls in the class are wearing dresses, that means 80% of 60, or 48 girls, are wearing dresses.
Therefore, the fraction of the class that are girls with dresses is 48/100, which can be simplified to 12/25.