If cos theta=- sqrt 3/ 2 and pi< theta< 3 pi 2 , are the values of sin and tan

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?

You are at a restaurant and owe $56.20 for your meal. you want to leave an 18% tip. approximately how much is your tip?