The probability that a person completes a particular task in less than 15 minutes is 0.4 Jeffrey selects 20 people at random and asks them to complete the task. The random variable, $$\(X\)$$, represents the number of people who complete the task in less than 15 minutes. (a) Find $$\(\mathrm{P}(5 \leqslant X< 8)\)$$ (3) Mia takes a random sample of 140 people. Using a normal approximation, the probability that fewer than $$\(n\)$$ of these 140 people complete the task in less than 15 minutes is 0.0239 to 4 decimal places. (b) Find the value of $$\(n\)$$ Show your working clearly. (6)

Answer:

Knowledge points:

Solution: