Probability Tes...

There are three boxes, each containing a different number of light bulbs. The first box has 10 bulbs, of which four are dead, the second box has six bulbs, of which one is dead, and the third box has eight bulbs of which three are dead. What is the probability of a dead bulb being selected when a bulb is chosen at random from one of the three boxes?

Suppose that two factories supply light bulbs to the market. Factory X's bulbs work for over $$5000$$ hours in $$99\%$$ of cases, whereas factory Y's bulbs work for over $$5000$$ hours in $$95\%$$ of cases. It is known that factory X supplies $$60\%$$ of the total bulbs available. What is the chance that a purchased bulb will work for longer than $$5000$$ hours?

If $$X$$ is a discrete random variable then which of the following is correct?

A letter is known to have come either from TATANAGAR or from CALCUTTA. On the envelope just two Consecutive letters TA are visible. What is the probability that the letters came from TATANAGAR ? 

For the events $$A$$ and $$B, P(A) = \dfrac {3}{4}, P(B) = \dfrac {1}{5}, P(A\cap B) = \dfrac {1}{20}$$ then $$P(A/B) =$$ ___________.

The probability that the bag contains 2 balls of each colour, is 

A random variable $$X$$ has the following probability distribution:

The distribution of a random variable X is given below:  

Let the p.m.f. of a random variable $$X$$ be -
$$P(x) = \dfrac {3 - x}{10}$$ for $$x = -1, 0, 1, 2 $$ otherwise
Then $$E(X)$$ is _________.

There is a probability that 4 out of 10 students appearing in CA CPT exams will qualify for CA course after passing CA CPT exam, the probability that of 5 students none will join CA course is.......