Elitmus
Exam
Numerical Ability
Probability
A box Contain 3 Red and 2 White balls.the balls are taken out without replacement what is the probability that one of the White ball is always taken out at the End??
Read Solution (Total 4)
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- if any of the white ball can come last then
any of the three red balls and one of the white balls should be taken out first
so..4/5*3/4*2/3*1/2=1/5 - 10 years agoHelpfull: Yes(21) No(1)
- if any of the white ball can come last then
any of the three red balls and one of the white balls should be taken out first
i,e. (4/5)*(3/4)*(2/3)=2/5 Ans.
- 10 years agoHelpfull: Yes(17) No(6)
- for 1st ball probability ( including one white ) = 4/5
then it is done without replacement..so for 2nd withdrawal = 3/4
then for 3rd..= 2/3.
hence answer = 4/5*3/4*2/3 = 2/5 - 10 years agoHelpfull: Yes(9) No(3)
- ns-4/10 i.e 2/5
total possibilities=5!/(3!*2!)=10
possibility that white is last = 4!/(3!*1!)=4
so,probability=4/10=2/5 - 7 years agoHelpfull: Yes(0) No(0)
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