+0  
 
0
221
1
avatar

United Airlines' flights from Denver to Seattle are on time 50 % of the time. Suppose 9 flights are randomly selected, and the number on-time flights is recorded. Round answers to 3 significant figures.

(a) The probability that exactly 4 flights are on time is =

(b) The probability that at most 3 flights are on time is =

(c) The probability that at least 8 flights are on time is =

 Feb 9, 2020
 #1
avatar+21955 
0

1) Exactly 4 of 9:  9C4 · (0.50)4 · (0.50)5

 

2) At most 3 of 9:  9C0 · (0.50)0 · (0.50)9  +  9C1 · (0.50)1 · (0.50)8  · 9C2 · (0.50)2 · (0.50)7 · 9C3 · (0.50)3 · (0.50)6

 

3)  At least 8:  9C8 · (0.50)8 · (0.50)1  +  9C9 · (0.50)9 · (0.50)1

 Feb 9, 2020

22 Online Users

avatar