You can put this solution on YOUR website! d+n = 25 subtract d from both sides:
n = 25-d I'll use this value for n next:
0.10d+0.05n = 1.85
0.10d+0.05(25-d)= 1.85
0.10d+1.25-0.05d = 1.85
0.05d = 0.60
d = 12 he has 12 dimes and 25-12 = 13 nickels
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Check:
12*0.10 = 1.2
13*0.05 = 0.65
. . . .--------
Total . . 1.85 Correct