A train runs first half of the distance at 40 km/hr and the remaining half at 60 km/hr. What is the
average speed for the entire journey?

• In such cases, if two speeds are x and y, then
  average speed = 2*x*y/(x+y)
  
  so here av speed = 2*40*60/100 = 48 km/hr
• 13 years agoHelpfull: Yes(29) No(1)
• The answer is 48kmph
  Let the total distance=2xkm
  To cover first half(xkm), time taken=x/40
  To cover the balancex km, time taken=x/60
  Total time taken x/40+x/60=5x/120
  Average speed= Total distance/total time taken=48kmph
• 13 years agoHelpfull: Yes(7) No(1)
• Average Speed = 2 *s1 *s2 / s1 + s2
  = 2 *40 * 60 / (40+ 60) = 48 km/hr
• 12 years agoHelpfull: Yes(3) No(0)
• there are two ways to solve this questions. firstly,
  -if two speeds are given then formula used is 2xy/(x+y).
  so answer is 2*40*60/(4+60)=48 kmph
  -second way is:-
  let total distance=x
  acc. to question, x/2 distance covered with 40 kmph speed and remaining x/2 distance with 60 kmph speed.
  as, time = distance/speed.
  so, total time taken = (x/2)/40(=t1) + (x/2)/60(=t2)=x/80 + x/120= 200x/9600
  so average speed is= total distance/ total time= x/(200x/9600) =48 kmph is the answer
• 7 years agoHelpfull: Yes(0) No(0)