A participated in cycling contest and he drove the lap at the rate of 6kmph, 12kmph, 18kmph, 24kmph..What is his average speed?

a) 15kmph b)18kmph c)14.25 d)11.52

• 11.52
  =4x/(x/6 +x/12 + x/18 +x/24)
  =11.52
  
  
• 8 years agoHelpfull: Yes(19) No(0)
• Assume the length of the lap is 72 kmph (LCM 6,12,18 and 24)
  Then his friend will take 12 hours, 6 hours, 4 hours and 3 hours respectively at the rate of 6,12,18 and 24 kmph. Total time taken 25 hours. Total distance 288 km
  288/25 = 11.52 kmph
  (We will get this same answer irrespective of whatever we assume the lap length. However, taking the LCM of the speeds has made the solution much easier.)
• 8 years agoHelpfull: Yes(10) No(0)
• 11.52
  http://www.careersvalley.com/infosys-practice-sample-aptitude-questions
• 8 years agoHelpfull: Yes(8) No(1)
• if u travel 3 diferent distances with diferent speeds say x,y,z then avg speed is (D1+D2+D3)/(D1/X+D2/Y+D3/Z)
  HERE it is given 4 difrnt speeds and say distance be X THEN AVG SPEED IS (X+X+X+X)/(X/6+X/12+X/18+X/24)=4X*72/25X=11.52
• 8 years agoHelpfull: Yes(7) No(0)
• average formula=(6+12+18+24)/4=60/4
  ans:15Kmph
• 8 years agoHelpfull: Yes(4) No(34)
• the concept of average speed is = total distance/total time
  =4x/(x/6+x/12+x/18+x/24)
  x=11.52
• 8 years agoHelpfull: Yes(4) No(1)
• (6+12+18+24)/4=15
  therefore ans is 15.
• 8 years agoHelpfull: Yes(1) No(6)
• 6+12+18+24=60/4=15kmph
• 8 years agoHelpfull: Yes(1) No(5)
• answer is 1) .15kmph
• 8 years agoHelpfull: Yes(1) No(4)
• 15km,6+12+18+24=70/4=15
• 8 years agoHelpfull: Yes(0) No(6)
• 15,The average of 6,12,18,24 is 60%4=15
• 8 years agoHelpfull: Yes(0) No(5)