Question 19754
Let nickets represent x
Let dimes represent y
x+y=21
y=21-x (equation 1)

dimes=10 (x100)
nickels=5 (x100)
sum=165 (x100)

5(x)+10(y)=165 (Sub in equation 1)
5x+10(21-x)=165
5x+210-10x=165
-5x=-45
x=9
21-9= 12
Therefore, there are 9 nickels and 12 dimes