Quick questions on Probability: Venn diagrams, addition and multiplication rules - WJEC A-Level Maths

4short Q&A pairs drawn directly from our worked dot-point answer. For full context and worked exam questions, read the parent dot-point page.

What are probability of events?

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The probability of an event

A

P(A) = \dfrac{\text{favourable outcomes}}{\text{total outcomes}}

for equally likely outcomes, with

0 \le P(A) \le 1

. The complement rule gives

P(\text{not } A) = 1 - P(A)

, which is often the quickest route to "at least one" probabilities.

What is q1?

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P(A) = 0.6

and

P(A')

is its complement. Find

P(A')

. [1 mark]

What is q2?

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Two fair coins are tossed. Find the probability of exactly one head. [2 marks]

What is q3?

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Events

A

and

B

are mutually exclusive with

P(A) = 0.3

P(B) = 0.45

. Find

P(A \cup B)

. [2 marks]

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