Algebra word problem

Question

A textbook store sold a combined total of 476

 psychology and history textbooks in a week. The number of history textbooks sold was 72

 less than the number of psychology textbooks sold. How many textbooks of each type were sold?

Answer 1

p+h=476, h=p-72

p + p-72 = 476

2p = 548

p = 548/2 = 274 psych books

h =274-72 = 202 history books