Answer:
52 dimes and 28 nickels
Step-by-step explanation:
n = number of nickels
d = number of dimes
n+d = 80 the number of coins he got
Multiply the number of nickels times .05 plus the number of dimes times .10 to equal the amount of money he got
.05n + .10d = 6.60
Divide this equation by .05
.05n/.05 + .10/.05 = 6.60/.05
n + 2d = 132
n+d = 80
Multiply by -1
-n-d=-80
Add this to n+2d = 132
n+2d=132
-n-d=-80
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d = 52
Now we need to solve for n
n+d = 80
n+52 = 80
Subtract 52 from each side
n+52-52= 80-52
n = 28
