A basket ball is dropped from a height of 20 feet .It bounces back each time to a height which is one half of the height of the last bounce. How far approximately ball have travelled before it comes to rest?

a.30 feet
b.40 feet
c.60 feet
d. can't be determined

• first the ball will travel 20 feet before reaching the ground then it will bounce back to 10 ft nd return to ground covrng 10 ft nd then bounce to 5 ft which will make it an infinite GP with r=1/2
  so total distance would be
  20 + 20/(1-1/2) =60 ft
• 7 years agoHelpfull: Yes(7) No(1)
• here the basket ball dropped from a height of 20 ft and it bounces back to a height which is half of the height last bounce so it is in G.P
  Sn = 20 + 10 + 5 + 2.5 +.......
  here a=20
  r=1/2
  n=∞
  in case of r < 1 and n=∞ for such condition
  Sn = a/(1-r)
  i.e
  Sn = 20/(1-1/2)
  i.e Sn = 40
  so the answer is 40 feet
• 7 years agoHelpfull: Yes(2) No(1)
• 20+10+10+5+5+2,5+2.5+1.25+1.25+0.75+0.75=60
• 7 years agoHelpfull: Yes(1) No(1)
• sum of infinite GP
  where a = 20 and r = 1/2
  ANS 60
• 7 years agoHelpfull: Yes(1) No(0)