Lois and peter are driving from camden, new jersey to central fall, rhode island, the two cities are 280 miles away from each other, and they plan to drive at 60 miles per hour the whole trip

They have to travel 280 miles and are going 60mph.
280/60 will give you the hours, which is 4.667 hours.
Peter is more correct the Lois, so I would say Peter is reasonable and Lois is not.

To estimate how long it will take them at 50mph, just do the same thing again. :)
I hope this helps. Comment if you have any more questions.