Can i get help solving C

Computer keyboard failures can be attributed to electrical defects or mechanical defects. A repair facility currently has 25 failed keyboards, 7 of which have electrical defects and 18 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)? 177100 g9 ways (b) In how many ways can a sample of 6 keyboards be selected so that exactly two have an electrical defect? 64260 'f ways @f a sample of 6 keyboards is randomly selected, what is the probability that at least 5 of these will have a mechanical defect? (Round your answer to four decimal places.) .3870 x