Selling Price after a 10% Profit Margin is applied to an item that Cost $90

Given: Cost = $90,  Profit Margin = 10%
Profit Margin as a Decimal: 10% = 0.1
Formula:
Selling Price =  

Cost/ 1 – Profit Margin as a Decimal

Selling Price =  

$90/ 1 – 0.1

Selling Price =  

$90/ 0.9

Selling Price = $100
Notes:
Profit = Selling Price – Cost = $100 – $90 = $10
Markup Amount = Profit = $10
Markup Percentage =  

Markup Amount/ Cost

=  

$10/ $90

= 0.1111 = 11.11%