Question

A 15 pound bag of ice costs $ 1.80. Give the unit rate.

Answer 1

We can use a rule of three simple, direct proportion to solve this problem.
15 pounds correspond to $1.80, then the question is to find the price of one pound, the called unit rate. We state the rule of three:
15 pound ---->  $1.80
 1 pound -----> x
x = (1)(1.80)/15
x = 0.12
Therefore, each pound costs $0.12 that is the unit rate in pounds