Computer keyboard failures can be attributed to electri cal defects or mechanical defects A repair facility cur rently 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 5 of these keyboards for a thorough inspection without regard to order b c In how many ways can a sample of 5 keyboards be selected so that exactly two have an electrical defect If a sample of 5 keyboards is randomly selected what is the probability that at least 4 of these will have a mechanical defect