Question 753689
informally this problem only requires a working knowledge of counting money

12 dimes: $1.20
3 nickels:$0.15

buck thirty five!


formally:

coins: n+d=15
cash value: 0.05n+0.10d=$1.35 (which we multiply by 20 for convenience)
n+2d=27

then

(n+2d)-(n+d)=27-15


d=12

do n=3




:)