Hey there! I'm happy to help!
We see that the cupcakes are $2, but for every 8 you buy you get 1 free.
So, if we buy 8 cupcakes, we will be paying $16, but we will actually be receiving 9 donuts, so that means that for every $16 we pay, we get 9 donuts.
Let's see how many times $16 goes into $80.
80/16=5
So, this means that our $16 that gives us 9 donuts was done 5 times, which totals up to 80 dollars. Let's multiply our donuts now.
9*5=45
So, Fatimah will get 45 donuts during the promotion.
Have a wonderful day and keep on learning! :D