Question

A manufacturing firm just received a shipment of 20 assembly parts, of slightly varied sizes, from a vendor. The manager knows that there are only 15 parts in the shipment that would be suitable. He examines these parts one at a time.

a. Find the probability that the first part is suitable. (Round your answer to 2 decimal places.)
b. If the first part is suitable, find the probability that the second part is also suitable. (Round your answer to 4 decimal places.)
c. If the first part is suitable, find the probability that the second part is not suitable. (Round your answer to 4 decimal places.)

Answer 1

Explanation:

Given that a manufacturing firm just received a shipment of 20 assembly parts, of slightly varied sizes, from a vendor. The manager knows that there are only 15 parts in the shipment that would be suitable.

a) The probability that the first part is suitable.

= no of suitable/total =
`(15)/(20) =0.75`

b) the probability that the second part is also suitable/first part was suitable

= Prob that first two parts suitable/Prob first part suitable

=
`((15C2)/(20C2) )/(0.75) \\= 0.7368`

c) If the first part is suitable, find the probability that the second part is not suitable

= Prob I part suitable and second not suitable/Prob first part suitable

=
`((15)/(20)(5)/(19) )/(0.75) \\= 0.2632`