You have a dish full of nickels and quarters. if there are 16 coins together worth $2.20, how many of each coin do you have?
need two equations and solve!
it already provides you with one equation. which is:
n + q = 16

N is how many nickels, q is how many quarters. since each n is worth 5 cents, and each q is worth 25 cents,
5n+25q=220
And you already have n+q=16
Multiply both sides in n+q=16 by 5 and you'll get 5n+5q=80
Subtract "5n+5q=80" from "5n+25q=220" leaving you with 20q=140, which simplifies to q=7. That is 7 quarters, leaving you with 16-7=9 nickels.

2xy/9 is the answer to this problem