Answer:
(n*80)/100=f
Explanation:
If it's multiple choice, I don't know the choices. I'd say:
n = number of dollars it costs:
f = final price
(n*80)/100=f
It will work for any given amount:
Let's say this item was 3 dollars.
Using the formula (n*80)/100=f where n is 3 in this situation we get:
(3*80)/100=f
240/100=f
f=$2.40
The final price of the item was $2.40 with a 20% discount.