I think I have to set up a system here:
Sarah has 600 quarters and dimes in her piggy bank which totals $123.75 how many quarters does she have?
+128460 Let q be the number of quarters and d be the number of dimes
Then we have this system :
q + d = 600 → d = 600 - q (1)
.25q + .10d = 123.75 (2)
Sub (1) into (2) for d and we have that
.25q + .10 ( 600 - q) = 123.75 simplify
.25q + 60 -.10q = 123.75
.15q + 60 = 123.75 subtract 60 from both sides
.15q = 63.75 divide both sides by .15
q = 425 → she has 425 quarters
