There are two boxes one containing 39 red balls the other containing 26 green balls You are allowed to move

Initially probability is never greater than 1. it always lies b/w 0 and 1. If the problem is solved the answer would be , first move 38 red balls from 1st box (leaving one red ball) to the 2nd box. then probability would be 1/2(1)+1/2(38/64)
=0.80 apprx. !!! where 64 is sum of red and green balls in the second box.
10 years agoHelpfull: Yes(48) No(2)

choosing a box at random from 2 boxes is=> 2c1
since already required box is choosen from the 2 boxes so req is box containing red balls....
so for choosing red ball from the choosen box is=> 39c1
so, total = 2c1*39c1 => 2*39 => 78 (i.e.,approx 80)
so, ANS IS 80
10 years agoHelpfull: Yes(7) No(9)
for maximizing the number of red balls, we will leave 1 red ball in the first box and shift the remaining 38 balls into the 2nd box...
now we have 2 boxes,one with 1 red ball and another with 38 red and 26 green balls..
now for the calculating the maximum probability,

the probability of choosing the first box is 1/2 as we have to chose 1 box out of 2... and then choosing the red ball in it is 1/1 because there is only 1 ball left.... (1/2)*(1/1)=(1/2)..... eq(i)

similarly for the second box.
probability of choosing the second box is (1/2) and red balls is (38/64)
where 38 are the no of red balls in the second box..and 64 are the total no of balls..ie red + green...
hence probability = (1/2)*(38/64) ....eq(ii)

on adding both the probabilities total probability = .64%
10 years agoHelpfull: Yes(5) No(6)
sorry .79=.80
10 years agoHelpfull: Yes(4) No(1)
For probability of choosing red ball is to be maximum, we have to
-move all red balls to other box.
probability of choosing box= 1/2

ans will be-- 1/2*1+1/2*38/64
= .64 is ans,,, options are wrongly written.
10 years agoHelpfull: Yes(2) No(11)
answer is:0.80;
((1/2)*1)+((1/2)*38/64)=0.80
10 years agoHelpfull: Yes(2) No(0)
Ans. Well Keep a single red ball in 1 box and move 38 red balls to the other

1st box = 1R
2nd box = 38R + 26G

p(red) = 1/2 * 1 + 1/2 * 38/64 ≈ 0.8
10 years agoHelpfull: Yes(1) No(0)
The options are wrong, how can Probability be ever greater than '1' !!
The correct answer is 51/64
7 years agoHelpfull: Yes(1) No(0)
ans will be .8
10 years agoHelpfull: Yes(0) No(1)
box n ball we cannt choose ...it's selected at random so i guess .80 is nt d correct ans.
10 years agoHelpfull: Yes(0) No(2)
correct ans=80
10 years agoHelpfull: Yes(0) No(0)

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