A unit rate tells you what the cost or how much you get from 1 unit of something. You can calculate it by dividing. You could either find out how many bowls you can buy with $1(by dividing 6/13.20) or you could find out how much 1 bowl cost(by dividing 13.20/6). They most likely want the second one.
13.20 / 6 = 2.2
So 1 bowl cost $2.20, this is our unit rate.
