Question

The time required to deliver and install a computer at a customer's location is t= 4 + d over r, where t is time in hours, d is the distance, in miles, from the warehouse to the customer's location, and r is the average speed of the delivery truck. If it takes 6.2 hours for the employee to deliver and install a computer for a customer located 100 miles from the warehouse, what is the average speed of the delivery truck?

Answer 1

`t=4+(d)/(r) \\ \\ t=6.2 \ [h] \\ d=100 \ [miles] \\ \\ 6.2=4+(100)/(r) \\ 6.2-4=(100)/(r) \\ 2.2=(100)/(r) \\ 2.2r=100 \\ r=(100)/(2.2) \\ r=45 (5)/(11) \\ r \approx 45.45 \ [(miles)/(h)]`

The average speed of the delivery truck is about 45.45 miles per hour.