Question 336979

Time = Distance / speed
time taken by me = 50km
speed = 83 km/h
time = 50/83 hours = 0.60 hours
..
Friend 's speed = 92km/h
time = 50 /92
= 0.54 hours.
Time he has to wait = 0.6 - 0.54 
=0.06 hours 
= 0.06 * 60 = 3.6 minutes