Cost of an item given Selling Price of $10 and a 66.67% Markup on Cost

Given: Selling Price = $10,  Markup = 66.67%
Markup as a Decimal: 66.67% = 0.6667
Formula:
Cost =  

Selling Price/ 1 + Markup as a Decimal

Cost =  

$10/ 1 + 0.6667

Cost =  

$10/ 1.6667

Cost = $6
Notes:
Markup Amount = Selling Price – Cost = $10 – $6 = $4
Profit = Markup Amount = $4
Profit Margin =  

Profit/ Selling Price

=  

$4/ $10

= 0.4 = 40%