A textbook store sold a combined total of 405 math and chemistry textbooks in a week. The number of math textbooks sold was two times the number of chemistry textbooks sold. How many textbooks of each type were sold?
You can think of this question like the photos attached above.
Also, a friendly reminder (I am sure that you know this already though) that variables cannot be capital letters (only lowercase). I used to make (and still make) this mistake a lot when writing equations, so I just thought that this reminder might be helpful.