Question

If car travel 150 k.m in 5 hours how much time it will take to travel 420 meters

Answer 1

distance=150km
time=5hrs
speed=dist/ time
150/5
30km/hr

now,
dist =420m. 420/1000km
speed=30km/hr
time=dist/ speed
0.42/30
=0.014hour
0.014×60
0.84minutes

Answer 2

150 km traveled  in  5 hours .
1 km (1000m)    in    5/150 hrs = 1/30 hrs = 2 min = 120 sec

So  420 m traveled in 120*420/1000 = 50.4 seconds  or  0.84 min