Person travels from A- to b in 9km/hr, and B to A in 4 Km/hr. What is the average speed?

• x=9,y=4
  average speed = (2xy)/(x+y)
  = (2*9*4)/(4+9)
  = 72/13
  = 5.54
• 12 years agoHelpfull: Yes(5) No(0)
• let A and B are x Km apart.
  so total distance cover by a person from A to B and B to A is 2x Km .and total time taken by him to cover 2x distance is=((x/4)+(x/9))=13x/36.
  as we know speed= distance/time.
  so average speed= (total distance covered for whole journey)/(total time require).so
  average speed=2x/(13x/36).=72/13=5.538km/hr.
• 12 years agoHelpfull: Yes(1) No(0)
• simple formula = (2* s1 * s2)/(s1 + s2)
  put values 2*9*4/(9+4)=72/13=5.54
• 12 years agoHelpfull: Yes(0) No(1)
• The formula to solve these average speed questions is : (2*ab)/(a+b) - where a represents the first speed and b represents 2nd speed.
  
  Now your answer would be (2*9*4)/(9+4) = 5.5384615 = 5.53
• 12 years agoHelpfull: Yes(0) No(1)
• average speed:2xy/(x+y)km/hr
  so,2*9*4/(9+4)=72/13=5.538km/hr
• 12 years agoHelpfull: Yes(0) No(0)