Theory question 105
ProbabilityThe probabilities that Ade, Kujo and Fati will pass an examination are 2/3, 5/8 and 3/4 respectively. Find the probability that: (a) the three (b) none of them; (c) Ade and Kujo only; will pass the examination.
Show the model answer
Model answer
(a) 2/3 × 5/8 × 3/4 = 5/16.
(b) 1/3 × 3/8 × 1/4 = 1/32.
(c) Ade and Kujo pass, Fati fails: 2/3 × 5/8 × 1/4 = 5/48.
Explanation
'Only' means the third person must fail, so use 1 − 3/4 for Fati.