algebra
posted by dayalyn .
Tristan has $3.75 in quarters and dimes. She has 21 coins. How many of each coin does she have?

quarters  x
dimes  21x
25x + 10(21x) = 375
25x + 210  10x = 375
15x = 165
x = 11
Tristan has 11 quarters and 10 dimes