A bin with nine mechanical parts contains ve parts from comp

A bin with nine mechanical parts, contains ve parts from company A and four

parts from company B. Suppose that we select three parts from this bin. Compute

(1)

The number of dierent possible selections,

(2)

The number of dierent possible selections that contain at least one part from company

A and at least one part from company B,

(3)

The probability of selecting no parts from company A or no parts from company B

Solution

A bin with nine mechanical parts, contains five parts from company A and four

parts from company B. Suppose that we select three parts from this bin. Compute

(1) The number of different possible selections,

9c3=84

(2) The number of different possible selections that contain at least one part from company

A and at least one part from company B,

5c1*4c2+5c2*2c1 =30+20=50

(3) The probability of selecting no parts from company A or no parts from company B

5c0*4c3 +5c3*4c0=14

P=14/84=0.1667