Answer: 12 nickels and 25 quarters.
Explanation:
Setting up the equations:
37 = q + n
for q = number of quarters, n = number of nickels
6.85 = 0.25*q + 0.05*n
685 = 25*q + 5*n
137 = 5*q + n
with n = 37 - q
137 = 5*q + (37 - q)
137 = 4*q + 37
100 = 4q
q = 25
n = 37 - 25 = 12
12 nickels and 25 quarters.
from MysticAlanCheng