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?

Guest Feb 19, 2020

#1**+1 **

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

CPhill Feb 19, 2020