Question 753100
number of coins: n+q=15

amt. of money: 0.05n+0.25q=3.55

for convenience we multiply by 20:

20(0.05n+0.25q)=20(3.55)

n+5q=71

Now we subtract the coins equation from this one...

(n+5q)-(n+q)=71-15

4q=56
q=14

therefore there is 1 nickel



:)