store solda combined totalof 412 biology and math booksin a week. the number of biology textbooks sold was three times the number of math books sold. how many textbooks of each type were sold?

The answer is that 103 math books were sold and 309 biology books were sold because if you multiply 103 by 3 you will get 309 but then you will still need to add the 103 that we found in the first place which would all add up to 412