The speed is 70 mph, that is, 70 miles per hour.
Since we have 60 minutes in 1 hour, this is the same as 70 miles per 60 minutes.
The more time the truck travles, further it will go, so this is direclty proportional.
We can use rule of three to answer.
time | distance
60 | 70
56 | x
Thus:
Thus, at this speed, the truck can travle approximately 65.3 miles in 56 minutes.