Question

You are traveling long distance for the first time in your new car. If the polynomial 90d^2 + 30d represents the miles traveled and you have traveled for 15d hours, find the average speed in the simplest form.

Answer 1

The average speed is 6 (3d+1) miles per hour

Answer 2

The polynomial 90d^2 + 30d represents the total distance traveled in miles, not the speed. To find the average speed, we need to divide the distance traveled by the time taken.

If we have traveled for 15d hours, then the distance traveled is:

90d^2 + 30d miles

The average speed is:

(distance traveled) / (time taken) = (90d^2 + 30d) / (15d) = 6(15d^2 + 5d) / (15d) = 6(3d + 1) miles per hour

Therefore, the average speed is 6(3d + 1) miles per hour, or simply 18d + 6 miles per hour.