Question about algebra

Question

A childs piggy back contains 19 coins considered of nickels dimes and quarters the total amount of money in the bank is $3.05 if the number of quarters is 1 more than twice the number of nickels find the number of each type of coin in the bank?

please solve it by using two variables x and y and by using substitution method

Answer 1

N+D+Q = 19

Q=1+2N

5N+10D + 25Q = 305

let N=x=number of nickels

let D=y = number of dimes

Q = 1+2x = number of quarters

x+y +1+2x =19

3x + y = 18

6x + 2y = 36

5x + 10y + 25(1+2x) = 305

55x + 10y = 280

11x + 2y = 56

6x + 2y = 36 subtract to get

5x = 20

x = 4 nickels

y = 6 dimes

1+2x = 9 quarters