Question

A woman has 31 coins in her pocket, all of which are dimes and quarters. If the total value of the coins is $ 5.20, how many dimes and how many quarters does she have?

Answer 1

D+Q = 31

10D + 25Q = 595

10D + 10Q = 310

subtract to get

15Q = 285 Q = 285/15 = 19 quarters D = 31-19 = 12 dimes