Probability

Which statement best summarizes the chapter "Probability"?

1. The chapter studies only statistics.
2. The chapter introduces the concept of probability, equally likely outcomes, sample space, favourable outcomes, and calculation of probabilities for simple events involving coins, dice, cards, and everyday situations.
3. The chapter studies only geometry.
4. The chapter has no practical applications.

Which of the following is an impossible event?

1. Getting Head on a coin toss
2. Rolling number 3 on a die
3. Rolling number 8 on a standard die
4. Drawing a Queen from cards

The sum of the probabilities of an event and its complement is:

1. 0
2. 1
3. 2
4. 1/2

Which experiment has equally likely outcomes?

1. Tossing a fair coin
2. Picking a defective bulb from mixed bulbs
3. Selecting a student based on marks
4. Predicting rainfall

A bag contains 5 red and 3 blue balls. The probability of selecting a blue ball is:

1. 3/8
2. 5/8
3. 1/2
4. 1/3

If one card is selected from a deck of 52 cards, the probability of selecting a King is:

1. 1/13
2. 1/4
3. 1/2
4. 4/13

The probability of drawing a red card from a deck of 52 cards is:

1. 1/4
2. 1/2
3. 3/4
4. 1/13

Which of the following can never be a probability?

1. 0
2. 1/4
3. 1
4. 5/4

A fair die is rolled once. The probability of getting an even number is:

1. 1/6
2. 1/3
3. 1/2
4. 2/3

A fair coin is tossed once. The probability of getting a head is:

1. 1
2. 1/2
3. 1/3
4. 2

The probability of a certain event is:

1. 0
2. 1
3. 1/2
4. 2

Probability of an event is defined as:

1. Number of favourable outcomes × Total outcomes
2. Number of favourable outcomes ÷ Total number of equally likely outcomes
3. Total outcomes ÷ Favourable outcomes
4. Number of impossible outcomes ÷ Total outcomes

500 packets, testing faulty devices. Probability all 4 devices without fault (300 packets out of 500)

1. 0.1
2. 0.2
3. 0.6
4. 0.4

Die thrown 1000 times. Probability of getting outcome 6 is (frequency=180)

1. 0.5
2. 0.180
3. 1
4. 0.33

50 seeds from 5 bags. Probability more than 40 germinated in a bag (bags B,C,E) is

1. 0
2. 0.60
3. 0.5
4. 0.7

400 students math test. Probability student scored more than 50 marks (100+30=130 students)

1. 0.39
2. 3.6
3. 3.9
4. 0.325

Factory batteries surveyed. Probability battery lasts more than 36 months (540+200 out of 1000)

1. 0.56
2. 0.74
3. 0.85
4. 0.68

Family of 3 children has at least one boy. Probability is

1. 1/8
2. 3/8
3. 7/8
4. 5/8

Non-leap year has 53 Saturdays. Probability is

1. 1/7
2. 2/7
3. 1/7
4. 3/7

Book of 100 pages opened at random. Probability of doublet page (11,22,...99) is

1. 9/100
2. 9/100
3. 1/11
4. 1/10

Coin tossed twice. Probability of at least one head is

1. 3/4
2. 3/4
3. 1/4
4. none

Die thrown. Probability of number greater than 2 OR even is

1. 5/6
2. 2/3
3. 1/2
4. none

Card from 100 cards (1–100). Probability of perfect square is

1. 1/25
2. 1/10
3. 3/10
4. 1/50

Random number from 1–25. Probability of prime is

1. 9/25
2. 9/25
3. 2/5
4. 1/5

Two dice thrown. Probability of difference=1 is

1. 5/18
2. 5/18
3. 1/6
4. none

Bag: 3 white, 5 red balls. Probability of red is

1. 5/8
2. 3/8
3. 1/8
4. none

Die rolled. Probability of even number is

1. 1/6
2. 1/2
3. 1/3
4. none

Two numbers chosen from 1–5. Probability of consecutive numbers is

1. 2/5
2. 2/5
3. 2/5
4. 1/5

Card drawn from 52. Probability of jack or king is

1. 1/26
2. 2/13
3. 4/13
4. none

Probability leap year has 52 Mondays and 53 Sundays is

1. 2/7
2. 1/7
3. 3/7
4. 4/7

3 letters into 3 envelopes randomly. Probability all in correct envelopes is

1. 1/6
2. 0
3. 1/3
4. 1

Single throw of two dice. Probability of sum=10 is

1. 1/18
2. 1/12
3. 1/12
4. none

P(guessing correct answer)=x/12. P(not guessing)=2/3. Value of x is

1. 2
2. 3
3. 4
4. 6

Digit chosen from 1–9. Probability of odd number is

1. 4/9
2. 5/9
3. 1/9
4. 2/3

Tank: 5 male, 8 female fish. Probability of male fish is

1. 5/13
2. 8/13
3. 5/8
4. 13/5

Letter chosen from ASSASSINATION. Probability of vowel is

1. 6/13
2. 7/13
3. 6/13
4. 5/13

Savita and Hamida; probability both have same birthday is

1. 1/365
2. 1/365
3. 1/730
4. 1/183

1000 lottery tickets, 5 prizes. Probability of winning is

1. 0.006
2. 0.007
3. 0.005
4. 0.008

Tickets 1–20. Probability of multiple of 3 or 7 is

1. 2/5
2. 2/5
3. 3/5
4. none

Two dice. P(multiple of 2 on one, multiple of 3 on other) and P(same number on both)

1. 11/36 and 1/6
2. 11/36 and 1/6
3. 10/36 and 1/6
4. 9/36 and 1/6

Three unbiased coins. Probability of all heads AND one head are

1. 1/8 and 3/8
2. 3/8 and 1/8
3. 1/4 and 3/8
4. 1/8 and 1/2

Pair of dice thrown. Probability of sum=11 is

1. 1/36
2. 1/18
3. 1/18
4. 1/6

Bag with 4 red, 5 black, 6 white balls. Probability of not black is

1. 1/3
2. 4/3
3. 2/3
4. 5/3

Arrow spins 1–12. Probability of odd number is

1. 1/2
2. 1/2
3. 1/3
4. 1/6

10 books: 3 maths, 2 GK, 5 novels. Probability of novel is

1. 3/10
2. 2/10
3. 1/2
4. 1/2

Card drawn from pack of 52. Probability of face card is

1. 3/13
2. 12/52
3. 4/13
4. 1/52

9 cards numbered 1–9. Probability of multiple of 3 is

1. 1/3
2. 2/9
3. 4/9
4. 5/9

Probability of winning a game is 0.7. Probability of losing is

1. 0.4
2. 0.3
3. 0.2
4. 0.5

King, Queen, Jack of clubs removed from 52 cards. Probability of getting a heart OR a king is

1. 16/49
2. 17/49
3. 3/49
4. 13/49

Three coins tossed. Probability of at least one head is

1. 1/8
2. 3/8
3. 7/8
4. 6/8

Two dice. Probability of sum=6 is

1. 5/36
2. 5/36
3. 1/6
4. 1/12

Bag with 10 white balls, P(blue)=2×P(white). Number of blue balls is

1. 30
2. 25
3. 20
4. 45

Probability that randomly selected vowel is 'o'

1. 1/5
2. 2/5
3. 1/5
4. 2/5

Cards 2 to 101 in box. Probability of card with number less than 14 is

1. 6/50
2. 12/100
3. 6/100
4. 12/50

Bag with 5 red and 8 white balls. Probability of white ball is

1. 5/13
2. 8/15
3. 9/15
4. 8/13

Die thrown once. Probability of prime number is

1. 1/2
2. 1/3
3. 2/3
4. 1/5

Coin thrown twice. Probability of exactly one head is

1. 1/3
2. 1/2
3. 1/6
4. 1/4