It is given that
Speed of first van=40mph
Speed of second van=61mph
Distance=63 miles
We know that
Substitute distance =63 miles and speed=40mph, we get the time taken by the professor
Multiply by 60 to convert this time into minutes, we get
94.5 minutes taken by the professor.
Substitute distance =63 miles and speed=61mph in equation (1), we get the time taken by the student
Multiply by 60 to convert this time into minutes, we get
61.9 minutes taken by the student.