What is a square unit?

In the sixth grade 13 out of 20 students have a dog if there are 152 sixth grade students how many of them have a dog

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4

Angie has saved 3/8 of the amount she needs to buy a bike. clive has saved 7/10 of the amount he needs to buy a skateboard. what is the difference between clive's and angie's fraction of savings?