A unit rate can be represented as"The number of x's per 1." They are often given in scenarios of several days, and you need to calculate what happened in 1 day.
For example:
John sells 60 watermelons in 30 day. What is the unit rate of his sells?
If he sells 60 in 30 days, that means he sells 2 watermelons per day. Therefore, the unit rate is 2.