Selling Price after a 100% Markup is applied to an item that Cost $10

Given: Cost = $10,  Markup = 100%
Markup as a Decimal: 100% = 1
Formula:
Selling Price = Cost * (1 + Markup as a Decimal)
Selling Price = $10 * (1 + 1)
Selling Price = $10 * 2
Selling Price = $20
Notes:
Markup Amount = Selling Price – Cost = $20 – $10 = $10
Profit = Markup Amount = $10
Profit Margin =   =   = 0.5 = 50%