A man was travelling to a place 30 miles away from starting point. he was speeding at 60 miles/hr. but when he came back, his car got breakdown and half an hour was wasted in reparing that. altogether he took 1 hr for return journey. Find the avg. speed of the whole journey.

• time taken for return journey =1 hr so speed for return journey=30/1=30miles/hr
  so average spped =2*60*30/(60+30)=40 miles/hr.
• 13 years agoHelpfull: Yes(14) No(4)
• going journey take 1/2 hr = 30/60
  returning journey take (30miles/x)+(1/2)=1
  x = 60 miles/hr.
  so average speed is = (2 * x * y)/(x + y) = (2 * 60 * 60)/(60 + 60)=60 miles/hr
• 13 years agoHelpfull: Yes(7) No(9)
• 40 km/hr
• 13 years agoHelpfull: Yes(4) No(2)
• in 1/2 hours he will cover 30 miles( 60 miles/hr)
  when came back he takes 1 hours.
  so total time = 1.5 hours
  total distance = 60 miles
  av speed = 60/1.5 = 40miles/hr
  
• 13 years agoHelpfull: Yes(3) No(1)
• from origin to destination the speed = 60 miles/hr
  from destination to origin the speed = 30 miles/hr
  so the average speed=(2*60*30)/(60+30)=40 miles/hr
• 10 years agoHelpfull: Yes(1) No(0)
• 120 km/hr. one can reach 30 km in half an hour if he speeding at 60 km/hr.and 1/4 hr at 120km/hr. in question it is mentioned that total journey was about 1 hr.. so
  obviously it should be 120km/hr because 1/4 hr to reach the destination and 1/4hr to come back from the same + 1/2 hr wasted..hence 1 hr
• 13 years agoHelpfull: Yes(0) No(7)
• going journey take 1/2 hr = 30/60
  returning journey take (30miles/x)+(1/2)=1
  x = 60 miles/hr.
  so average speed is = (2 * x * y)/(x + y) = (2 * 60 * 60)/(60 + 60)=60 miles/hr
• 13 years agoHelpfull: Yes(0) No(2)