Final answer:
Edna will receive 9 free cupcakes for her order of 30 cupcakes, based on the promotion that gives 3 free cupcakes for every 10 purchased.
Step-by-step explanation:
The Mini sweets bake shop has a promotion where for every 10 cupcakes purchased, 3 free cupcakes are added to the order. To determine how many free cupcakes Edna will receive, we divide the total number of cupcakes she bought by 10 and then multiply the resulting quotient by 3.
Edna bought 30 cupcakes. So we first divide 30 by 10, which equals 3. This means for every 10 cupcakes, since she bought 30, we have three sets of 10. For each of these sets, she receives 3 free cupcakes. Therefore, we take the 3 sets and multiply it by 3 free cupcakes per set.
3 (sets of 10 cupcakes) \u00D7 3 (free cupcakes per set) = 9 free cupcakes
In conclusion, Edna will receive 9 free cupcakes added to her order of 30 cupcakes according to the bake shop's special promotion.