There are a total of coins when dimes and nickels are combined. The total amount is 80 cents. How many dimes and nickels are there, respectively?

Barrett is comparing the membership fees for two museums.the art museum charges a one-time fee of $8.25 plus $2.25 per month. the science museum charges a one-time fee of $10.75 plus $3.50 per month. how much does barrett save by joining the art museum instead of the science museum?