Mathematics 0580 · IGCSE · Probability of combined events

Probability of combined events — practice question

Bag $A$ and bag $B$ contain only red counters and blue counters. Stephan selects a counter at random from bag $A$, and Jen selects a counter at random from bag $B$. The probability that Stephan selects a red counter is 0.4. The probability that both Stephan and Jen select red counters is 0.25.
(main)[4]

Find the probability that Stephan and Jen both pick a blue counter.

Worked solution & mark scheme

This 4-mark question has a full step-by-step worked solution and mark scheme. One marking point: $\left(1-\frac{0.25}{0.4}\right)(1-0.4)$

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