Part (a)
It costs $31 to rent a bike for 7 hours.
So, in order to find how many hours of bike use a customer gets per dollar, we perform the quotient of these quantities that lead us to a rate with the units hours per dollar. That is we divide the number of hours by amount in dollars as shown below:
7 hours divided $31 = 7/31 h/$ which rounded to the nearest hundreth is:
0.23 hours per dollar.
Part (b)
It takes 36 pounds of seed to completely plant a 5-acre field.
We are asked to find the pounds of seed per acre. So we proceed as before making a quotient that contains the pounds in the numerator, and the number of acres in the denominator:
36 pounds/ 5 acres = 36/5 pounds/acre = 7.2 pounds/acre