# Test on probability

Total Questions:25 Total Time: 45 Min

Remaining:

## Questions 1 of 25

Question:If $$P\,(A) = 0.4,\,\,P\,(B) = x,\,\,P\,(A \cup B) = 0.7$$and the events A and B are mutually exclusive, then $$x =$$

### Answers Choices:

$$\frac{3}{{10}}$$

$$\frac{1}{2}$$

$$\frac{2}{5}$$

$$\frac{1}{5}$$

## Questions 2 of 25

Question:Let A and B be two events such that $$P\,(A) = 0.3$$ and $$P\,(A \cup B) = 0.8$$. If A and B are independent events, then $$P(B) =$$

### Answers Choices:

$$\frac{5}{6}$$

$$\frac{5}{7}$$

$$\frac{3}{5}$$

$$\frac{2}{5}$$

## Questions 3 of 25

Question:One card is drawn from a pack of 52 cards. The probability that it is a queen or heart is

### Answers Choices:

$$\frac{1}{{26}}$$

$$\frac{3}{{26}}$$

$$\frac{4}{{13}}$$

$$\frac{3}{{13}}$$

## Questions 4 of 25

Question:Let A and B be two events such that $$P\overline {(A \cup B)} = \frac{1}{6},P(A \cap B) = \frac{1}{4}$$ and $$P(\bar A) = \frac{1}{4},$$ where $$\bar A$$ stands for complement of event A. Then events A and B are

### Answers Choices:

Independent but not equally likely

Mutually exclusive and independent

Equally likely and mutually exclusive

Equally likely but not independent

## Questions 5 of 25

Question:If A and B are two independent events such that $$P\,(A) = \frac{1}{2},\,\,P(B) = \frac{1}{5},$$ then

### Answers Choices:

$$P\,\left( {\frac{A}{B}} \right) = \frac{1}{2}$$

$$P\,\left( {\frac{A}{{A \cup B}}} \right) = \frac{5}{6}$$

$$P\,\left( {\frac{{A \cap B}}{{A' \cup B'}}} \right) = 0$$

All of the above

## Questions 6 of 25

Question:A bag "A" contains 2 white and 3 red balls and bag "B" contains 4 white and 5 red balls. One ball is drawn at random from a randomly chosen bag and is found to be red. The probability that it was drawn from bag "B" was

### Answers Choices:

$$\frac{5}{{14}}$$

$$\frac{5}{{16}}$$

$$\frac{5}{{18}}$$

$$\frac{{25}}{{52}}$$

## Questions 7 of 25

Question:At least number of times a fair coin must be tossed so that the probability of getting at least one head is at least 0.8, is

7

6

5

None of these

## Questions 8 of 25

Question:The value of C for which $$P\,(X = k) = C{k^2}$$ can serve as the probability function of a random variable X that takes 0, 1, 2, 3, 4 is

### Answers Choices:

$$\frac{1}{{30}}$$

$$\frac{1}{{10}}$$

$$\frac{1}{3}$$

$$\frac{1}{{15}}$$

## Questions 9 of 25

Question:In a binomial distribution the probability of getting a success is 1/4 and standard deviation is 3, then its mean is

6

8

12

10

## Questions 10 of 25

Question:A card is drawn from a pack of 52 cards. If A = card is of diamond, B = card is an ace and $$A \cap B =$$card is ace of diamond, then events A and B are

### Answers Choices:

Independent

Mutually exclusive

Dependent

Equally likely