A parents has two children. If one of them is boy, then the probability that other is, also a boy, is

• 1/2

• 1/4

• 1/3

• None of these

A random variable X has the probability distribution

x	1	2	3	4	5	6	7	8
P(x)	0.15	0.23	0.12	.010	0.20	0.08	0.07	0.05

For the events E = {x is prime number} and F = {x < 4} the probability of P(E ∪ F) is

• 0.50

• 0.77

• 0.35

• 0.87

From a group of 8 boys and 3 girls, a commitee of 5 members to be formed. Find the probability that 2 particular girls are included in the committe is

• $\frac{4}{11}$

• $\frac{2}{11}$

• $\frac{6}{11}$

• $\frac{8}{11}$

A four digit number is to be formed using the digits 1, 2, 3 4, 5 6, 7 (no digit is being repeated in any number). Then, the probability that it is > 4000, is

• 3/2

• 1/2

• 4/7

• 3/7

If x follows the Binomial distribution with parameters n = 6 and p and 9P(X = 4) = P(X = 2), then p is

• 1/4

• 1/3

• 1/2

• 2/3

One card is drawn at random from a pack of playing cards the probability that it is an ace or black king or the queen of the heart will be

• $\frac{3}{52}$

• $\frac{7}{52}$

• $\frac{6}{52}$

• $\frac{1}{52}$

15 coins are tossed, then the probability of getting 10 heads will be

• $\frac{511}{32768}$

• $\frac{1001}{32768}$

• $\frac{3003}{32768}$

• $\frac{3005}{32768}$

198.

The odds against solving a problem by A and B are 3 : 2 and 2 : 1 respectively, then the probability that the problem will be solved, is

• $\frac{3}{5}$

• $\frac{2}{15}$

• $\frac{2}{5}$

• $\frac{11}{15}$

If random variable waiting time in minutes for bus and probability density function of x is given by

$$\begin{gathered} \mathrm{f}\left(\mathrm{x}\right) = \left\{\frac{1}{5}, 0 \le \mathrm{x} \le 5 \\ 0 , \mathrm{otherwise}\right\} \end{gathered}$$

then probability of waiting time not more than 4 minutes is equal to

• 0.3

• 0.8

• 0.2

• 0.5

If the probability density function of a random variable X is given as

xi	- 2	- 1	0	1	2
P(X = xi)	0.2	0.3	0.15	0.25	0.1

then F(0) is equal to

• P(X < 0)

• P(X > 0)

• 1 - P(X > 0)

• 1 - P(X < 0)