algebra
posted by Benjamin .
Militsa has 4 times as many nickels as dimes. Their total value is $8.10. How many of each coin does she have

Let N be the number of nickels and D be the number of dimes. Here is what you know:
N = 4D
10D + 5N = 810

Now substitute 4D for N
10D + 20D = 810
30D = 810
You take it from there 
30D=810 check
=D=810/30 108*.05+27*.1=8.1
=D=27 5.4+2.7=8.1
8.1=8.1
x=y*4
x=27*4
x=108
y=27 
85

jk idk how