Answer:
D - (D/5)
Explanation:
Let's imagine that D equals 100 dollars -
Well, we know that to get 20% of an amount, we need to divide the amount by five. So let's do that -
100 / 5 = 20
We now know that 20% of 100 dollars is equal to 20 dollars. We have now finished the first part. On to the second part.
We now need to take away 20% of 100 dollars off of 100 dollars - this is the price of the item after the discount.
100 - 20 = 80 dollars.
We now fit in D instead of 100 dollars -
D - (D/5)