An automobile travels 10km at a speed of 100kph, 40km at 80kph and a 3rd diatance at 50kph. If the average velocity for the trip is 70kph, what is the length of the 3rd distance travelled?

• let 3rd distance=x
  total distance=10+40+x
  total time taken=(10/100 +40/80 +x/50) hr
  avg vel=total distance/total time taken
  or 70=(10+40+x)/(10/100 +40/80 +x/50)
  or 50+x=7+35+7x/5
  or 2x/5=8
  or x=20
• 11 years agoHelpfull: Yes(1) No(0)
• Let,3rd Distance = x unit
  then,(10+40+x)/((10/100)+(40/80)+(x/50))=70
  then x=20
  Length of 3rd distance is 20km.
• 11 years agoHelpfull: Yes(0) No(0)