Mini Sweets bake shop is running a special on cupcakes. For every 10 cupcakes purchased, 3 free cupcakes are added to the order. Edna is getting treats for her class party. She bought 30 cupcakes.

How many free cupcakes will be added to Edna's order?

1 answer

Edna bought 30 cupcakes, and for every 10 cupcakes, 3 cupcakes are free, so Edna's order qualifies for 30/10 = <<30/10=3>>3 packs of free cupcakes.
Those 3 packs of free cupcakes would in total be: 3*3 = <<3*3=9>>9 cupcakes free. Answer: \boxed{9}.