There are 2 boxes with numerous balls in them. The box contains 13 red, 17 white balls. The second box contains 12 red and 8 green balls. If one of these selected at random and a ball is selected at random from the selected box, what is the probability that the selected ball will be white?

a. 17/30
b. 17/50
c. 17/60
d. 29/60

• c. 17/60
  Prob. of selecting the box,containing white ball= 1/2 &
  Prob. of selecting white ball in that box=17/30
  So probability of selecting white ball= (1/2)*(17/30)= 17/60
• 10 years agoHelpfull: Yes(3) No(0)
• probability of selecting either of the box=1/2
  no of white balls in box1=17(out of 30)
  probability of selecting white ball from box 1=1/2*17/30=17/60
  no of white balls in box2=0(out of 20)
  probability of selecting white ball from box 2=0
  so,probability that selected ball is white=17/60+0=17/60
• 10 years agoHelpfull: Yes(1) No(0)
• PROBABILITY OF PICKING UP WHITE BALL IS 0.5*(17/30)/(0.5*(13/30) +0.5*(17/30)+ 0.5*(12/20) +0.5(8/20))=17/30
• 10 years agoHelpfull: Yes(0) No(3)
• prob. of that selected ball is whilte=(1/2)((17/30)+(0/20))
  =17/60 ans..
• 10 years agoHelpfull: Yes(0) No(0)
• hello frnds...
  though the 2nd box does not have white ball so why to consider the 2nd box we can just pick the white ball from box 1 so the probability is 17/30
• 10 years agoHelpfull: Yes(0) No(0)
• box 1= 13 r box 2= 12 r
  17 w 8 g
  here we have to select the one box randomly.
  so probability of box 1 is 1/2
  so probability of box 2 is 1/2
  now we have to select the white ball from box 1 or box 2
  1/2(17/30)+1/2(0/20) [ note: there is no white ball in the box 2 so we took zero and total no. of balls from box 1 is 13+17=30 and similar to this box 2 total no of balls is 12+8=20]
  =17/60
• 4 years agoHelpfull: Yes(0) No(0)