Selling Price after a 66.67% Markup is applied to an item that Cost $6

Given: Cost = $6,  Markup = 66.67%
Markup as a Decimal: 66.67% = 0.6667
Formula:
Selling Price = Cost * (1 + Markup as a Decimal)
Selling Price = $6 * (1 + 0.6667)
Selling Price = $6 * 1.6667
Selling Price = $10
Notes:
Markup Amount = Selling Price – Cost = $10 – $6 = $4
Profit = Markup Amount = $4
Profit Margin =   =   = 0.4 = 40%