A textbook store sold a combined total of 232 sociology and psychology textbooks in a week

Question

A textbook store sold a combined total of 232 sociology and psychology textbooks in a week. The number of psychology textbooks sold was 76 less than the number of sociology textbooks sold. How many textbooks of each type were sold?

Answer 1

Let S = Sociology books

P = Psychology books

Then

S + P = 232 or S + (S - 76) = 232 or

2S = 308 S = 154 and P = S - 76 = 78

So

Sociology Books = 154

Psychology Books = 78