A random variable X has the following probability distribution

X = x1	1	2	3	4
P(X = x1)	0.1	.02	0.3	0.4

The mean and the standard deviation are respectively

• 3 and 2

• 3 and 1

• $3 \mathrm{and} \sqrt{3}$

• 2 and 1

172.

The probability distribution of a random variable X is given as

x	- 5	- 4	- 3	- 2	- 1	0	1	2	3	4	5
P(X = x)	p	2p	3p	4p	5p	7p	8p	9p	10p	11p	12p

Then, the value of p is

• $\frac{1}{72}$

• $\frac{3}{73}$

• $\frac{5}{72}$

• $\frac{1}{74}$

If n(A) = 43, n(B) = 51 and n(A ∪ B) = 75, then n[(A - B) $\cup$ (B - A)] is equal to

• 53

• 45

• 56

• 66

If five dices are tossed, then what is the probability that the five numbers shown will be different?

• $\frac{5}{54}$

• $\frac{5}{18}$

• $\frac{5}{27}$

• $\frac{5}{81}$

If the events A and B are independent and if $\mathrm{P}\left(\overline{\mathrm{A}}\right) = \frac{2}{3}, \mathrm{P}\left(\overline{\mathrm{B}}\right) = \frac{2}{7}$, then $\mathrm{P}\left(\mathrm{A} \cap \mathrm{B}\right)$ is equal to

• $\frac{4}{21}$

• $\frac{3}{21}$

• $\frac{5}{21}$

• $\frac{2}{21}$

Two fair dice are rolled. Then, the probability of getting a composite number as the sum of face values is equal to

• $\frac{7}{12}$

• $\frac{5}{12}$

• $\frac{1}{12}$

• $\frac{3}{4}$

Let S be the set of all 2 x 2 symmetric matrices whose entries are either zero or one. A matrix X is chosen from S. The probability that the determinant of X is not zero is

• 1/3

• 1/2

• 3/4

• 1/4

Two balls are selected from two black and two red balls. The probability that the two balls will have no black balls is

• 1/7

• 1/5

• 1/4

• 1/6

In a flight 50 people speak Hindi, 20 speak English and 10 speak both English and Hindi. The number of people who speak atleast one of the two languages is

• 40

• 50

• 20

• 60

Two dice are thrown simultaneously. What is the probability of getting two numbers whose product is even?

• 3/4

• 1/4

• 1/2

• 2/3