Pearson Edexcel IAL Mathematics S1.3.2 Sample space

Practise using sample spaces, complements, unions and conditional probability to calculate probabilities from tables, diagrams and contexts.

Exam points

use complements and unions to calculate P(A′), P(A ∪ B) or P(A ∩ B)
calculate conditional probabilities from Venn diagrams, tables or tree information
show a given probability by forming the correct numerator and conditioning event

[Maximum number: 2]

The events H and W are such that

\mathrm{P}(H)=\frac{3}{8} \quad \mathrm{P}(H \cup W)=\frac{3}{4}

Given that H and W are independent,

Find $\mathrm{P}\left(N^{\prime} \mid H\right)$

Given that W and N are mutually exclusive,

$\mathrm{P}\left(N^{\prime} \mid H\right)=\frac{\frac{3}{8}-\frac{1}{15}}{\frac{3}{8}} \text { or } \frac{\frac{9}{40}+\frac{1}{12}}{\frac{3}{8}} \text { or } 1-\frac{\frac{1}{15}}{\frac{3}{8}}$ $=\frac{37}{45} \quad=\text { awrt } 0.822$ }}

M1

A1

(2)

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S1.3.2 - Sample space question 1