Jennifer has 12 nickels and dimes. The value of her coins is $1

One Dollar and 80 cents.

Step-by-step explanation:

12 x 5 is 60. The amount of nickles multiplied by the value of one nickel which is 5 cents. Then you take the value of a dime and multiply it by the amount of dimes, 12. You get 120. Add 60 to 120 and you get 180. One Dollar is 100 cents, add 80 to 100 and you get one Dollar and 80 cents.