Let's play a game. If I went halfway to a town 60 km away at the speed of 30 km/hour, how fast do I have to go the rest of the way to have an average speed of 60 km/hour over the entire trip?

• If the distance travelled with differnt speed are equal then,
  avg speed is harmonic mean of the speeds i.e= 2*p*q/(p+q)
  where p and q are the speeds for travelling the two equal parts.
  here avg speed =60 and p=30 q=?
  substituing the value in eqn we cannot deduce the value of q or is infinite.
  Hence not possible to attain the avg speed no matter how fast you travel
• 10 years agoHelpfull: Yes(0) No(0)
• total distance = 120 km.
  if average distance = 60 km/h then it will take time = 2 h.
  up to 60 km average speed is 30 km/h. so it has taken 2 h already. so no possibility to cover next 60 km in 0 sec.
• 10 years agoHelpfull: Yes(0) No(0)