Theory question 105
ProbabilityThe probability that Abiola will be late to office on a given day is 2/5. In a given working week of six days, find, correct to four significant figures, the probability that he will: (a) be late for only 3 days; (b) not be late in the week; (c) be late throughout the six days.
Show the model answer
Model answer
Binomial: n = 6, p = 0.4, q = 0.6.
(a) ⁶C₃(0.4)³(0.6)³ = 20 × 0.064 × 0.216 = 0.2765.
(b) (0.6)⁶ = 0.04666.
(c) (0.4)⁶ = 0.004096.
Explanation
Each day is an independent trial with the same probability.