Question

Mitchell’s cell phone provider’s phone line is busy 80% of the time. In 12 calls, what is the probability that it will be busy at least 10 times?

Answer 1

Explanation:

Binomial distribution:
`X \sim B(n,p)`

where n is the number and p is the probability

Given:

• n = 12
• p = 0.8

`X \sim B(12,0.8)`

P(X ≥ 10) = 1 - P(X ≤ 9)

= 1 - 0.4416542515...

= 0.5583 (4 dp)