The first step we need to take is to find the length of the tires, the length of a circle can be determine by the following expression:

Where d is the diameter of the circle. So we have:

Now we need to convert the number of revolutions per minutes to revolutions per hours, to do that we have to multiply by 60.

The tire rotates around itself 24,000 times per hour. We can multiply this number with the length of the tire in order to determine the speed in inches per hours:

Now we need to convert this from inches per hours to miles per hour. To do this we have to divide by 63360.

The speed of the truck will be approximately 50 miles per hour.