A person says that their speed while going to a city was 10mph however while
returning as there is no much traffic they came with a speed of 15mph. what is their
average speed?

• Avg speed= 2xy/x+y
  Hence Ans: 12
• 10 years agoHelpfull: Yes(36) No(0)
• Don't fall in the trap of just averaging the 2 speeds. Overall average speed is not (S1+S2)/2. ***
  Total average speed is simply = Total distance/Total time
  Lets say,
  D = distance travelled by the car in EACH direction
  t1 = time spent on onward trip
  t2 = time spent on return trip
  Thus, the total distance travelled by the car = D+D= 2D
  And, by the formula, Speed = Distance/Time
  S1 = D/t1 => t1 = D/S1
  S2 = D/t2 => t2 = D/S2
  Total average speed = Total Distance/Total time = 2D/(t1+t2) = 2D/(D/S1+D/S2) = 2S1*S2/(S1+S2)
  
• 10 years agoHelpfull: Yes(23) No(0)
• ans is 12(2xy/x+y)
• 10 years agoHelpfull: Yes(6) No(0)
• 12 as avg speed =(2*10*15)/(10+15)
• 10 years agoHelpfull: Yes(4) No(0)
• average speed=(2*x*y)/(x+y)
  therefore average speed=2*10*15/15+10=12mph
• 10 years agoHelpfull: Yes(2) No(0)
• average speed=2xy/x+y;
  so,(2*10*15)/10+15
  so ans 12
• 10 years agoHelpfull: Yes(2) No(0)
• acco to frmla......
  2xy/(x+y)
  2*10*15/25=12.
• 9 years agoHelpfull: Yes(2) No(0)
• consider distance was 30mil
  so going time 10*3 hrs = 30mil
  on return 15*2 = 30mil
  
  avg speed = total distance/total time
  so = 60/5 = 12mph
• 10 years agoHelpfull: Yes(1) No(0)
• 12 as avg speed =(2*10*15)/(10+15)
• 9 years agoHelpfull: Yes(1) No(0)
• 12.5 km/h.
• 9 years agoHelpfull: Yes(1) No(5)
• 12
  as this is
• 8 years agoHelpfull: Yes(1) No(0)
• (2*10*15)/(10+15)=12
• 10 years agoHelpfull: Yes(0) No(0)
• avg speed s =2xy/x+y
  x=10
  y=15
  s= (2*10*15)/(10+15)
  s= 12kmph ans
• 10 years agoHelpfull: Yes(0) No(0)
• avg speed 12 answer
• 10 years agoHelpfull: Yes(0) No(0)
• since Total avg speed=total dist travelled/total time taken
  =2D/(D/15 +D/10)=12 mph
• 10 years agoHelpfull: Yes(0) No(0)
• avg = 2xy/x+y
  because distance is constant or same.
  Hence ans is
  Avg = 2*10*15/10+15
  avg= 2*10*15/25
  Avg=12mph
• 7 years agoHelpfull: Yes(0) No(0)
• 10+15=25.
  25/2=12.5
• 6 years agoHelpfull: Yes(0) No(0)
• 12 2xy/x+y
• 6 years agoHelpfull: Yes(0) No(0)
• 12
  2v1v2/(v1+v2)
• 6 years agoHelpfull: Yes(0) No(0)
• avg speed=2xy/x+y
  =2*10*15/10+15
  =12
  ans is 12mph
• 6 years agoHelpfull: Yes(0) No(0)