I’ve been looking at the highlighted questions in the attachment for a bit and I still don’t really get how the answers are what they are (e.g for Q19c isn’t it just 1/3?). Any worked solutions or explanations would be very much appreciated! Probability is actually my opp 
oh and if it helps it’s from Cambridge Maths Ext 1 Ex 12G
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oh and if it helps it’s from Cambridge Maths Ext 1 Ex 12G
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