[Insert generic name here] is trying to bake a yellow cake because [reasons]. This recipe will make one whole cake.

He wants to make three cakes instead of one. How much of each item should be used in the new (scaled-up) recipe?


I don't know exactly how your teacher wants you to write out the work, but I have it pretty simple there. It's not like math is tailored to a specific process; any sort of reasonable work should do.
Good luck!