Question about calculating Selling Price of a product

[gmagerr]

I hope this is the correct forum to post this question. I'm going through one of the rea tests, and there's a question about calculating Selling Price of a product that doesn't make sense to me. The question is something like this

Toy company A wants to calculate the selling price on some widgets they bought. The cost of each widget is $400, and they want a markup of 60 percent. What should their selling price be?

I selected $640, but the answer is $1000

The formula to calculate selling price is SP = Cost + Markup the cost is $400, and the markup is 60% so wouldn't it be $400 + $240 = $640? I must be doing something wrong, can someone help?

thanks