I have 36 nickles and dimes worth 2.20 how many nickles and dimes do i have

Ok so

n=number of nickes

d=number of dimes

d+n=36

worth

2.20=worth of nickles+worth of dimes

worth of nickles=number of nickes times 0.05=0.05n

worth of dimes=number of dimes times 0.10 so

2.2=0.05n+0.1d

so we have

n+d=36

2.2=0.05n+0.1d

multiply the second equaiton by - 10

-22=-0.5n-1d

add to first equation

36+n+d

-22=-0.5n-d +

14=0.5n+0d

14=0.5n

divide both sides by 0.5

28=n

subsitute

n+d=36

28+d=36

subtract 28

d=8

28 nickles and 8 dimes