Hello! So this is pretty simple multiplication and make sure you read the question carefully
It gives you a list of ingredients to make a cake, in which results in 12 slices as provided.
Simply take 36 and divide it by 12 - 36/12
Which gives you 3!
To check you answer take
12 (slices) x 3 (times the recipe) = 36 (slices)
Hope this helps you!! Have a wonderful day <3