Danielle sells cupcakes. The first 10 cupcakes a customer purchases costs x dollars each. Every cupcake purchased after 10, each cost 50% of x. If Lucy spent $21.00 on 11 of Danielle’s cupcakes, what is the value of x?

Answer 1

The first 10 cupcakes cost x dollars each for a total cost of 10*x = <<10*x=10x>>10x dollars.
The next cupcake cost 50% of x which is x/2 = 1/2*x
The total cost of 11 cupcakes is 21 dollars.
The first 10 cupcakes cost 10x dollars and the next one cost x/2 for a total of 10x + x/2 = <<10*x+x/2=10.5x>>10.5x dollars.
If 10.5x = 21 then x = 21/10.5 = <<21/10.5=2>>2. Answer: \boxed{2}.