How could you find the number of different combinations of 6 letters in a computer password?

An advertising firm has an old computer that can prepare a whole mailing in 6 hours. with the of newer model the job is complete in 2 hours. how long would it take the newer model to do the job alone?

You are a clerk at convenience store. a customer owes 11.69 for a bag of potatoes chips. she gives you a five dollar bill. how much change should the customer receive?

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?