Question

Kate has some dimes and quarters. If she has 23 coins worth a total of $3.50, how many of each type of coin does she have?

Answer 1

23=d+q, d=23-q

350=10d+25q, using d from above

350=10(23-q)+25q

350=230-10q+25q

120=15q

q=120/15

q=8, and since d=23-q

d=23-8=15

So there are 15 dimes and 8 quarters