A man jogs at 6 mph over a certain journey and walks over the same route at 4 mph. What is his average speed for the journey?
a) 2.4 mph (b) 4 mph (c) 4.8 mph (d) 5 mph

• Ans:c)4.8 mph
  Formula for calculating the avg speed for same distannce = 2xy/(x+y)where x= speed of forward one and y =speed of return one
  Average Speed = 2(6)4/(6+4)
  =24/5 =4.8mph
• 14 years agoHelpfull: Yes(9) No(0)
• ans is c)4.8
  take a harmonic means of these two speeds,to get average speed
  thatis avg speed = (2*6*4)/(6+4)=48/10=4.8
  
• 14 years agoHelpfull: Yes(4) No(0)
• use the formula
  (2*x*y)/(x+y)
  so
  (2*6*4)/(6+4) = 4.8 mph
• 14 years agoHelpfull: Yes(3) No(0)
• let distance be x.....
  so avg speed is total dist/total time= 2x/(x/6 + x/4 ) = 2/(1/6 + 1/4)= 4.8mph
• 14 years agoHelpfull: Yes(3) No(0)
• 2*6*4/(6+4)=4.8
  formula is 2xy/(x+y)
• 14 years agoHelpfull: Yes(3) No(0)
• Answer is 4.8 mph
  
• 9 years agoHelpfull: Yes(0) No(0)