Okay so, the formula we can use for this problem will be x= 410/.82, x being the original price of the TV. The .82 was figured to make up for the 18% lost from the original price. 410/.82=500. so the original price of the TV would be $500. To check our answer we can multiply 500 by the sale price and subtract that amount from the original $500. Like so: 500-(500*.18)=410.