a textbook store...

Question

A textbook store sold a combined total of
304
biology and psychology textbooks in a week. The number of biology textbooks sold was three times the number of psychology textbooks sold. How many textbooks of each type were sold?

Answer 1

Let x = the number of psychology textbooks sold

Let 3x = the number of biology textbooks sold

x + 3x = 304

4x = 304

x = 76 psychology books

3x = 3(76) = 228 biology books