How would i estimate to find how many students are in fourth grade?

Which expression is equivalent to7_/x^2 ÷ 5_/y^3? assume y# 0

Haruka hiked several kilometers in the morning. she hiked only 66 kilometers in the afternoon, which was 25% less than she had hiked in the morning. how many kilometers did haruka hike in all?

Which of the following transformations will always produce a congruent figure?