M drves alng d permtr of a square of side 10kns.she drvs alng d frst side at 10kmph,2nd 20kmph,3rd 30kmph,4th 40kmph..avg speed
30,18, 19.2, 20

• IT's 19.2
  i explain... we have to apply formula 2xy/x+y three timesss
  for first 10 &20 avreage speed will be 400/30=40/3 for secound 30& 40
  
  avrage speed=2400/70=240/7... and finally apply avg formula between this two speed
  
  
  avg speed=2*40/3*240/7 /40/3+240/7 = = =19.2 answer
• 12 years agoHelpfull: Yes(7) No(3)
• total time=10/10+10/20+10/30+10/40
  total d=40
  avg v=40/(25/12)=19.2
• 12 years agoHelpfull: Yes(5) No(0)