Question

Computer keyboard failures can be attributed to electrical defects or mechanical defects. A repair facility currently has 25 failed keyboards, 8 of which have electrical defects and 17 of which have mechanical defects.

(a)

How many ways are there to randomly select 7 of these keyboards for a thorough inspection (without regard to order)?

ways

(b)

In how many ways can a sample of 7 keyboards be selected so that exactly two have an electrical defect?

ways

(c)

If a sample of 7 keyboards is randomly selected, what is the probability that at least 6 of these will have a mechanical defect? (Round your answer to four decimal places.)

Answer 1

Thank you.