A car driver, driving in a fog, passes a pedestrian who was walking at the rate of 2 km/h in the same direction. The pedestrian could see the car for 6 minutes and it was visible to him up to a distance of 0.6 km. What was the speed of the car ?
A 30 km/h
B 15 km/h
C 20 km/h
D 8 km/h

• 8 km/hr
  In 6 minutes, the walking man covered a distance of 2*6/60= 0.2 kms
  During 6 mins, the distance travelled by car = 0.2+0.6=0.8 kms
  so speed of car = 0.8*60/6 = 8 km/hr
• 13 years agoHelpfull: Yes(7) No(0)
• car travelled 0.6 km in 6 min. i.e 6/60=0.1 hr.
  relative speed of car =0.6/0.1= 6km/hr
  relative speed = actual speed of car-speed of pedestrain. =>6=x-2 =>x=8
  so, actual speed of car = 8km/hr
• 13 years agoHelpfull: Yes(3) No(1)
• Relative speed formula in same direction
  S1-S2=(L1+L2)/T
  So in the question s1=2km/hr
  L1+L2=0.6km
  T=6min so to covert in hour
  6min=1/10hr
  So put all the values in the formula
  S1-2=(0.6)*10
  S1=8km/hr
• 6 years agoHelpfull: Yes(0) No(0)
• speed of the car=600m/360sec=5/3 m/s=6kmph
  but this speed is relative to the pedestrain.
  therefore the actual speed of the 6+2(speed of the walker)= 8kmph.
  Answer: option D, 8kmph
• 6 years agoHelpfull: Yes(0) No(0)