If the area of a certain desert is three times the area of another desert the sum of their areas is 16,000,000 square miles find the area of each desert

First divide 16 mil by 4. That gets you 4 mil. Then (since one of the deserts is three times the size of the other) multiply one of them by three. Now, you have 12,000,000 and 4,000,000.

I’m pretty sure the answer is a