What is the unit rate of 15 laps in 3 days

The answer is going to be 5 laps per day because I did 15 laps/3days and divided each side by 3 which the answer is going to be 5/1 but it’s basically 5 since it’s going to be a whole number in this set. Therefore the unit rate of 15 laps in 3 days is going to be 5 laps per day.

A) for the n row: 22+(n-1)×6therefore,b) 100-22=78that means (n-1)×6=7878÷6=1313+1=1414th row has 100 seats

It should be a or d i’m not sure