EASY
Earn 100

A die is thrown. If it shows a six, we draw a ball from a bag consisting 2 black balls and 6 white balls. If it does not show a six, then we toss a coin. Then, the sample space of this experiment consists of (all balls are distinct)

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Important Questions on Probability

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Six persons A, B, C, X, Y & Z go for an interview. What is the probability of selection of A and Y in the interview?

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Assume that each born child is equally likely to be a boy or girl. If two families have two children each, then the conditional probability that all children are girls given that at least two are girls is:
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The probability of guessing correctly at least 8 out of 10 answers on a true-false type examination is
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Two letters are chosen from the letters of the word 'EQUATIONS'. The probability that one is vowel and the other is consonant is
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If A and B are any two events such that PA+PB-PA and B=PA, then
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A man speaks truth 2 out of 3 times. He picks one of the natural numbers in the set S={1,2,3,4,5,6,7} and reports that it is even. The probability that it is actually even is

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Let A and B be two events such that the probability that exactly one of them occurs is 25 and the probability that A or B occurs is 12, then the probability of both of them occur together is
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Three numbers are chosen at random without replacement from {1,2,3,,8}. The probability that their minimum is 3, given that their maximum is 6, is
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If A and B are two events such that PA0 and PBA=1, then
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A bag contains 4 red and 6 black balls. A ball is drawn at random from the bag, its color is observed and this ball along with two additional balls of the same color are returned to the bag. If now a ball is drawn at random from the bag, then the probability that this drawn ball is red, is:
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It is given that the events A and B are such that PA=14, PAB=12 and PBA=23. Then PB is
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If A and B are events with PAB=34,P A=23 and PAB=14 then PB is
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Let A and B are two independent events. If the probability that both A and B occur together is 16 and the probability that neither of them occurs is 13, then the probability of occurrence of A is
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In a college, 15th of the girls and 18th of the boys took part in a social camp. The total number of students in the college took part in the camp is:

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A die is thrown 7 times. What is the probability that an even number turns up at least 4 times?
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Two numbers are selected at random from the set 1,2,3,,13. If the sum of the selected numbers is even, the probability that both the numbers are odd is
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The probability that atleast one of the events A and B occur is 0.6. If A and B occur simultaneously with probability 0.2, then P(A¯)+P(B¯) is
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Let A and B  be two non-null events such that AB. Then, which of the following statements is always correct?
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For the following distribution function F(x) of a random variable X

x 1 2 3 4 5 6
F(x) 0.2 0.37 0.48 0.62 0.85 1

P 3<X 5=

EASY
An urn contains 5 red and 2 green balls. A ball is drawn at random from the urn. If the drawn ball is green, then a red ball is added to the urn and if the drawn ball is red, then a green ball is added to the urn; the original ball is not returned to the urn. Now, a second ball is drawn at random from it. The probability that the second ball is red, is: