CAIE S1 2007 November — Question 7

Exam BoardCAIE
ModuleS1 (Statistics 1)
Year2007
SessionNovember
TopicTree Diagrams
TypeCalculate end-outcome probability

7 Box \(A\) contains 5 red paper clips and 1 white paper clip. Box \(B\) contains 7 red paper clips and 2 white paper clips. One paper clip is taken at random from box \(A\) and transferred to box \(B\). One paper clip is then taken at random from box \(B\).
  1. Find the probability of taking both a white paper clip from box \(A\) and a red paper clip from box \(B\).
  2. Find the probability that the paper clip taken from box \(B\) is red.
  3. Find the probability that the paper clip taken from box \(A\) was red, given that the paper clip taken from box \(B\) is red.
  4. The random variable \(X\) denotes the number of times that a red paper clip is taken. Draw up a table to show the probability distribution of \(X\).