Jennifer had a total of 20 coins consisting of nickels and quarters. If the value of the coins was $1.80, how many quarters did she have?

N=nickles

q=quarters

n+q=20

5n+25q=180

divide last question by 5

n+5q=36

n+q=20

n+5q=36

multiply top equation by - 1 and add to 2nd equato

-n-q=-20

n+5q=36 +

0n+4q=16

4q=16

divide both sides by 4

q=4

4 quarters

You wouldn't be able to have the correct amount of coins with just quarters and nickles.