Probability distribution of random variable X is

X	-2	-1	0	1	2
P(X)	2/11	1/11	4/11	3/11	1/11

Then the value of E(X) is

A four digit number is formed by using the digits 1, 2, 4 and 5 with no repetition. The probability that the number is divisible by 5, is

The random variable X has the following probability distribution

such that E(x²) = 2E(x), then the value of b is:

Let A, B, C be three events. If the probability of occurring exactly one out of A and B is $\frac{3}{5}$, exactly one of B and C is $\frac{1}{5}$, exactly one of C and A is $\frac{3}{5}$ and that of occurring of three events is $\frac{4}{25}$, then the probability of occurring at least one of them is

A pair of dice is thrown then probability of getting sum of numbers on dice is '8', is:

Two cards are drawn successively with replacement from a well-shuffled deck of 52 cards. The probability distribution of number of aces is given by:

Five bad apples are mixed with 15 good apples accidently. Let the random variable X be the number of bad apples in a draw of two apples, then mean of X is