Question

A jacket is on sale for 20% off the regular price. The sale price is $50. What is the regular price of the jacket?

Answer 1

The regular price is `$62.50`.

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`:

`"      "p% "off     of  reg.price  is    sale price"`
`(100-p)%times"       "r"        "="        "s`

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

Answer 2

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

Hence

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*50/80=62.5`

Hence answer is $62.5