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Probability

Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.

Theoretical and relative frequency

Subtopic

Theoretical and relative frequency under Probability for Grade 11 IGCSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    A survey showed that 45 out of 150 people prefer tea over coffee. What is the relative frequency of people who prefer tea?

    A.

    0.450.45

    B.

    0.300.30

    C.

    0.150.15

    D.

    0.600.60

  2. 2.

    A student has 10 shirts: 3 white, 2 blue, and 5 grey. What is the probability of the student choosing a white shirt at random?

    A.

    0.30.3

    B.

    0.20.2

    C.

    0.50.5

    D.

    0.10.1

  3. 3.

    A spinner has 4 equal sections: 1, 2, 3, and 4. If spun once, what is the probability of getting a number less than 4?

    A.

    0.250.25

    B.

    0.500.50

    C.

    0.750.75

    D.

    1.001.00

Download the worksheet for Probability - Theoretical and relative frequency to practice offline. It includes additional chapter-level practice questions.

Combined events

Subtopic

Combined events under Probability for Grade 11 IGCSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    Events A,BA, B, and CC are mutually exclusive. P(A)=0.2,P(B)=0.3,P(C)=0.4P(A) = 0.2, P(B) = 0.3, P(C) = 0.4. What is the probability that A,BA, B, or CC occurs?

    A.

    0.0240.024

    B.

    0.90.9

    C.

    0.240.24

    D.

    0.50.5

  2. 2.

    A bag contains 2 red and 3 blue chips. A chip is drawn, replaced, and another is drawn. What is the probability that both are red?

    A.

    425\frac{4}{25}

    B.

    25\frac{2}{5}

    C.

    410\frac{4}{10}

    D.

    15\frac{1}{5}

  3. 3.

    A coin is tossed twice. What is the probability of getting at least one 'Head'?

    A.

    14\frac{1}{4}

    B.

    12\frac{1}{2}

    C.

    34\frac{3}{4}

    D.

    11

Download the worksheet for Probability - Combined events to practice offline. It includes additional chapter-level practice questions.

Tree diagrams

Subtopic

Tree diagrams under Probability for Grade 11 IGCSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    A tree diagram shows P(Win)=0.7P(\text{Win}) = 0.7. If two matches are played, what is the probability of winning the first match and losing the second?

    A.

    0.490.49

    B.

    0.210.21

    C.

    0.090.09

    D.

    0.300.30

  2. 2.

    A box contains 66 blue and 44 pink ribbons. A ribbon is selected and replaced. What is the probability of selecting a pink ribbon then another pink ribbon?

    A.

    0.160.16

    B.

    0.240.24

    C.

    0.360.36

    D.

    0.400.40

  3. 3.

    If you flip a coin (P(H)=0.5P(H)=0.5) and then roll a die (P(6)=1/6P(6)=1/6), what is the probability of getting a Head and then a 6?

    A.

    112\frac{1}{12}

    B.

    18\frac{1}{8}

    C.

    12\frac{1}{2}

    D.

    23\frac{2}{3}

Download the worksheet for Probability - Tree diagrams to practice offline. It includes additional chapter-level practice questions.

Conditional probability

Subtopic

Conditional probability under Probability for Grade 11 IGCSE.

About Topic & Revision

Preview questions (no answers)

  1. 1.

    If P(A)=0.9P(A) = 0.9 and P(B∣A)=0.1P(B|A) = 0.1, what is P(A∩B)P(A \cap B)?

    A.

    0.09

    B.

    0.1

    C.

    0.8

    D.

    0.99

  2. 2.

    A group of 40 people were asked if they like apples or oranges. 25 like apples, 20 like oranges, and 10 like both. If a person who likes oranges is chosen, what is the probability they also like apples?

    A.

    0.5

    B.

    0.25

    C.

    0.4

    D.

    0.625

  3. 3.

    The probability that it rains is 0.3. The probability that it rains and I use an umbrella is 0.24. If it rains, what is the probability I use an umbrella?

    A.

    0.8

    B.

    0.072

    C.

    0.54

    D.

    0.7

Download the worksheet for Probability - Conditional probability to practice offline. It includes additional chapter-level practice questions.