Question 365201
n+d = 15,
0.05n + 0.10d = 1.25.  The top equation gives d = 15-n.  Substituting into the bottom equation, gives:
0.05n + 0.10(15-n) = 1.25,
0.05n + 1.5-0.10n = 1.25,
-0.05n = -0.25
n = 5, the number of nickels,
d = 10, the number of dimes.