#### Explanation:

If the sale price is $50, and the sale is 20% off, that means the$50 represents the other 80% of the regular price—the part that you do pay. So then we ask ourselves, okay, $50 is 80 percent of... what? In math speak, that would be written as $50("is")80%("of")("regular price")
$50=80%" "times" "r Solving this for $r$, we get r=($50)/(80%)

We remind ourselves that the "percentage" symbol is just a shorthand for "divide this number by 100." The equation becomes

r=($50)/(80//100)=($50)/0.8=$62.50 So the regular price is$62.50.

## Bonus:

A general formula can be used for any regular price $r$, any percent discount $p$, and any sale price $s$:

$\text{ "p% "off of reg.price is sale price}$
(100-p)%times"       "r"        "="        "s

As long as we know two of the three variables $\left\{p , r , s\right\}$, we can solve for the third one.

Nov 29, 2016

The regular price is $62.50 [One more explanation as mentioned below] #### Explanation: Since the Jacket was sold 20% less than its original price, it means suppose the regular price of jacket is$100 so its 20% less is $80, but it sold in$50
If suppose the jacket was sold in $80 in place of it regular price$100, so what will be regular price if the jacket sold for $50 since, suppose sale price is$ 80 against its regular price $100 therefore what regular price will be, if jacket sold in$50
$100 \cdot \frac{50}{80} = 62.5$