Answer:
$850.00
Step-by-step explanation:
Lets start by calling the initial price of the TV to be P.
20% off means that we are paying 80% of the price which means that we are only paying: .8 * P
We know the sale price is $680.00, so we set that equal to .8 * P and solve.
We get P = $850.00 as the original price.