Answer: She has 40 nickels and 40 quarters .
Step-by-step explanation:
Let be "n" the number of nickels Theresa has and "q" the number of quarters Theresa has.
You know that she has a total of $12 in nickels and quarters. In cents, this is:
[tex]\$12*100=1,200\ cents[/tex]
Then, based on this you can write the following expression:
[tex]5n+25q=1,200[/tex]
Since [tex]n=q[/tex], you can rewrite it as:
[tex]5n+25n=1,200[/tex]
Solving for "n", you get:
[tex]30n=1,200\\\\n=\frac{1,200}{30}\\\\n=40[/tex]
Therefore she has 40 nickels and 40 quarters .