Computer keyboard failures can be attributed to electrical
defects or mechanical defects. A repair

facility currently has 25 failed keyboards, 6 of which have
electrical defects and 19 of which have

mechanical defects.

a. How many ways are there to randomly select 6 of these
keyboards for a thorough inspection

(without regard to order)?

b. In how many ways can a sample of 6 keyboards be selected so
that exactly three have a

mechanical defect?

c. If a sample of 6 keyboards is randomly selected, what is the
probability that no more than 2 of

these will have an electrical defect?