Five balls of different colours was on five different stairs.What is the probability that there was a pink ball on 4th stair and red ball on 5th stair.

• ans-1/20.
  1/5*1/4=1/20.
  
• 11 years agoHelpfull: Yes(40) No(1)
• p(pink on 4th and red on 5th)=3!(fixing those 2 and arranging rest 3)/5!(arranging all the 5 balls)
  therefore p=3!/5!=1/20
  ans =1/20
• 11 years agoHelpfull: Yes(10) No(0)
• n(E)=!1*!1*!3
  n(S)=!5
  n(P)=!3/!5=1/20
• 11 years agoHelpfull: Yes(3) No(0)
• pink ball==1/5
  red ball=1/4
  total probablity=(1/5*1/4)=1/20
• 11 years agoHelpfull: Yes(2) No(0)
• red ball on 5th stair: (1/6)*(1/5)
  (1/6)-probability of red color presence
  (1/5)-probability of 5th stair
  similarly for pink so ans= (1/30)*(1/30)= (1/900).
• 11 years agoHelpfull: Yes(1) No(6)
• 1/20. 3!*2!/5!
• 11 years agoHelpfull: Yes(1) No(3)
• 3!/5!=1/20
• 11 years agoHelpfull: Yes(1) No(0)
• ans:6/5^5
• 11 years agoHelpfull: Yes(0) No(4)