Question

United Airlines' flights from Boston to Dallas are on time 80 % of the time. Suppose 7 flights are randomly selected, and the number on-time flights is recorded. 1.The probability that at least 3 flights are on time is

Answer 1

Answer: 14.5

Explanation:

Given data:

Success rate = 80% = 0.8

No of flights = 7

No of failures = 1 – 0.8 = 0.2

Solution

at least 3 flights are on time is

= 7C3 * (0.80)^3 * (0.80)^1 + 7C7 * (0.80)^7 * (0.80)^1

= 35 * 0.512 * 0.8 + 1 * 0.21 * 0.8

= 14.336 + 0.168

= 14.5