Which is a unit rate? 4 dollars
————-
3 cans

5 students
——————
2 teachers

6 hours : 1 book
3 miles : 2 days

Natasha spent 1 1/2 hours on the beach. she fell asleep for 3/4 of the time she was on the beach and then woke up with a terrible sunburn. how many hours was natasha asleep on the beach?

An investment decreases in value by 30% in the first year and decreases by 40% in the second year. what is the percent decrease in percentage in the investment after two years

Elizabeth claims that the fourth root of 2 can be expressed as 2^m since (2^m)^n = 2. find the values of m and n for the case where elizabeth's claim is true.