Question 1023777
the basic formulas involved are:


sale price = original price minus discount.
discount = original price * discount percent / 100.


let s represent the sale price.
let p represent the original price.
let d represent the discount.
let k represent the discount percent.


the above formulas become:


s = p - d
d = p * k/100


we know that s = 315.
we know that k = 30.


formulas become:


315 = p - d
d = p * 30/100


simplify these formulas to get:


315 = p - d
d = .3p


since d = .3p, then the first formula can be shown as:


315 = p - .3p, after we replace d with its equivalent value of .3p.


simplify to get 315 = .7p.


divide both sides of this equation by .7 to get:


315/.7 = p


solve for p to get p = 450.


the original price is 450.


30% of 450 = 135.


450 - 135 = 315, which is the sale price.


numbers look good.


solution is that the original price is 450.


it doesn't really matter what variable names you choose as long as you can keep track as to what variable name represents what.