Question

At a speed of 35km an hour, a car take 5 hours for journey. How long will it take at a speed of 50 km/hr to complete the journey.

Answer 1

first we have to find what is given in the question.
case 1 car takes 5 hr.
speed =35kmph=(35*1000)/(60*60)=9.72m/sec.
time=5 hours =5*60*60=18000 sec.
distance= speed*time
=9.72*18000
=174.96km
case 2
speed must be converted into m/sec
i.e. 13.88m/sec
distance will be same
distance=speed* time.
174.96*1000=13.88*x
x will be in sec. so convert into hours by dividing by60*60

x= 3hr 50 min