Calculate Probability as a Number

Q. A box contains slips numbered 1, 2, 3, 4. Another box contains slips numbered 1, 2, 3. If one slip is taken from each, what is the probability of getting a sum which is a multiple of three?

1. $\frac{1}{3}$
2. $1$
3. $\frac{2}{3}$
4. $\frac{1}{8}$

Q. 16 people study French, 21 study Spanish and total number of students studying these languages is 30. Consider the experiment of randomly selecting students and the events X and Y defined as
X = {Student studying French is selected}
Y = {Student studying Spanish is selected}
X and Y are mutually exclusive events.

1. False
2. True

Q.

A bag contains 10 blue balls and 12 yellow balls. What is the probability of getting a yellow ball ?

1. $\frac{5}{11}$

2. $\frac{1}{11}$

3. $\frac{5}{13}$

4. $\frac{6}{11}$

Q.

The probability of guessing the correct answer to certain test questions is $\frac{y}{4}$. If the probability of not guessing the correct answer to these questions is $\frac{3}{4}$, then the value of y is:

1. $\frac{1}{4}$

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

3. 1

4. 0

Q.

There are 13 red balls, 6 green balls and 6 blue balls in a bag. What is the probability of drawing (i) red ball (ii) blue ball or a green ball? [2 MARKS]

Q.

In a cricket match , the player hits a 4 in every 12 balls. What is the probablity of him not hitting a 4 .

1. $1$

2. $\frac{1}{12}$

3. $\frac{2}{3}$

4. $\frac{3}{4}$

Q. A box contains slips numbered 1, 2, 3, 4. Another box contains slips numbered 1, 2, 3. If one slip is taken from each, what is the probability of getting a sum which is a multiple of three?

1. $\frac{1}{3}$
2. $1$
3. $\frac{2}{3}$
4. $\frac{1}{8}$

Q.

A number x is chosen at random from the numbers -3, -2, -1, 0, 1, 2, 3, the probability that |x| < 2 is

1. $\frac{5}{7}$

2. $\frac{2}{7}$

3. $\frac{1}{7}$

4. $\frac{3}{7}$

Q.

A game of chance consists of spinning an arrow which comes to rest pointing at one of the numbers 1, 2, 3, 4, 5, 6, 7, 8 (see figure) and these are equally likely outcomes. What is the probability that it will point at a number less than 9?

1. 0

2. 1

3. 0.5

4. 0.86

Q.

There are 60 students in a class among which 30 are girls.In another class, there are 50 students out of which 25 are boys.If one student from each class is selected, what is the probability that both are boys ?

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

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

3. $\frac{1}{4}$

4. $\frac{2}{3}$

Q.

$\text{Which of the following can be the probability of getting 7 as the outcome of rolling a dice?}$

1. $0.5$
2. $0$
3. $0.25$
4. $1$

Q. There are 300 shelves in a gym. Each shelf has 2 lockers. The gym just opened today. Ram and Arjun are its first 2 customers. It is given that Ram is allotted one locker in the ${235}^{th}$ shelf. What is the probability that Arjun also is allotted a locker in the ${235}^{th}$ shelf?

Q. A box contains slips numbered 1, 2, 3, 4. Another box contains slips numbered 1, 2, 3. If one slip is taken from each, what is the probability of getting a sum which is a multiple of three?

Q.

From 2012 to 2018 (including both) if a year is selected at random, the probability of having 365 days in that year is___.

1. $\frac{3}{7}$

2. $\frac{4}{7}$

3. $\frac{5}{7}$

4. $\frac{2}{7}$

Q.

The probability of getting a sum of 13 when two dice are thrown simultaneously is___.

1. 1

2. 0

3. 1/2

4. 3/4

Q.

An unbiased coin is tossed. Then the chance of getting head is .

1. 1
2. 2
3. $\frac{1}{2}$
4. $\frac{3}{4}$

Q.

From a well-shuffled deck of 52 cards, a card is picked at random. (i) Find the probability of the card being a queen of spades. (ii) If the card drawn at first is a queen of spade and is not replaced, what is the probability of getting a card which is a spade?

1. (i) $\frac{1}{52}$ (ii) $\frac{12}{51}$

2. (i) $\frac{13}{52}$ (ii) $\frac{1}{51}$

3. (i) $\frac{1}{4}$ (ii) $\frac{1}{12}$

4. (i) $\frac{1}{26}$ (ii) $\frac{12}{51}$

Q.

A number x is chosen at random from the numbers -3, -2, -1, 0, 1, 2, 3, the probability that |x| < 2 is

1. $\frac{5}{7}$

2. $\frac{2}{7}$

3. $\frac{3}{7}$

4. $\frac{1}{7}$

Q.

If you take a random 4 digit number, what is the probability that (i)the ten's place digit is greater than the unit's place digit
(ii) that the leftmost digit is a multiple of 3 (iii) the rightmost digit is a multiple of 3. [4 MARKS]

Q.

There are 121 articles in a bag. Out of which 11 are defective articles. If you just pick one article at random, (i) what is the probability of picking the non-defective article? (ii) If the article drawn the first time is non-defective and is not replaced, then find the probability of getting the defective article in the next draw.

1. (i) $\frac{11}{121}$ (ii) $\frac{12}{121}$

2. (i) $\frac{10}{11}$ (ii) $\frac{11}{120}$

3. (i) $\frac{12}{121}$ (ii) $\frac{10}{11}$

4. (i) $\frac{10}{11}$ (ii) $\frac{1}{12}$

Q.

If a letter is selected randomly from the word 'PROBABILITY', what is the probability that it is a vowel?

1. 2/11

2. 3/11

3. 5/11

4. 4/11

Q.

In a single throw of dice, find the probability of getting a number greater than 2.

1. 2/3

2. 2/5

3. 1/2

4. 1

Q. A letter of English alphabet is chosen at random. What is the probability that the chosen letter is a consonant?

Q.

There are 300 shelves in a gym. Each shelf has 2 lockers. The gym just opened today. Ram and Arjun are its first 2 customers. It is given that Ram is allotted one locker in the ${235}^{th}$ shelf. What is the probability that Arjun also is allotted a locker in the ${235}^{th}$ shelf?

1. $\frac{299}{300}$

2. $\frac{1}{300}$

3. $\frac{1}{600}$

4. $\frac{599}{600}$