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Question 1
5 marksThere are some red counters and some blue counters in a bag.
The ratio of red counters to blue counters is 3:1.
Two counters are removed at random.
The probability that both the counters taken are blue is 120\displaystyle \frac{1}{20}201
Why do we multiply probabilities when a question asks for "both counters are blue"?
Revision notes for AQA GCSE Maths Probability Equation Questions. Open the guide for explanations and worked examples. Written against the AQA GCSE Maths (8300) specification, so the content matches what's examinable rather than general Maths background.
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A bag contains xxx blue counters and 5 red counters. Two counters are taken without replacement, and the probability that both are blue is 310\frac{3}{10}103. Which equation should you write?