Answer:
14 dimes and 17 quarters
Step-by-step explanation:
d and q are the number of dimes and quarters, respectively.
"31 coins, all of which are dimes and quarters."
d+q = 31
d = 31-q
"the value of the coins is $5.65"
0.10d + 0.25q = 5.65
substitution
0.10(31-q) + 0.25q = 5.65
3.10-0.10q + 0.25q = 5.65
0.15q = 2.55
q = 17
d = 31-q = 14
14 dimes and 17 quarters
