2012 SAJC P2 Q7

2012 SAJC P2 Q7

8 marks
Prelims
Free
  1. Given that the two events \(A\) and \(B\) are such that \(\mathrm{P}(A|B)=\frac{2}{3},\,\,\mathrm{P}(A\cap B'\,)=\frac{1}{4}\) and \(\mathrm{P}(A\cap B)=\frac{5}{12}\),
    1. determine if \(A\) and \(B\) are independent,[1]
    2. find \(\mathrm{P}(A\cup B)\).[2]
  2. Ali and Bob take turns to shoot an arrow in an Archery training session. The probability that Ali hits the bull’s eye is \(0.3\) and for Bob, it is \(0.4\). Ali shoots first.
    Find the probability that Ali hits the bull’s eye first.[3]
  3. Calvin, his parents and \(7\) other people are seated in a round table of \(10\). Find the probability that his parents are seated together but Calvin is not seated beside either of his parents.[2]

Video Solution:

Default solution

Timothy Gan
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Answer:(a) (i) Since \({P(A) = \frac{2}{3} = P(A\vert{}B)}\), therefore \({A}\) and \({B}\) are independent (ii) \({\frac{7}{8}}\) (b) \({\frac{15}{29}}\) (c) \({\frac{1}{6}}\)

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