Exam-Style Question on Probability Distribution
A mathematics exam-style question with a worked solution that can be revealed gradually
Question id: 430. This question is similar to one that appeared on an IB AA Standard paper in 2019. The use of a calculator is allowed.
Amelia selects a disc from a bag containing 5 green discs, 4 blue discs and 3 red discs.
She wins £1 for a green disc, £3 for a blue disc, and £7 for a red disk. The game costs £4 to play.
(a) Calculate the expected gain for this game, and hence show that the game is not fair.
After a while, \(n\) red discs are added and Amelia wins £5 if she selects one. The game is now fair.
(b) Create an equation to represent this information.
(c) Hence, calculate the value of \(n\).
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