Question

A textbook store sold a combined total of 411 psychology and history textbooks in a week. The number of history textbooks sold was 69 less than the number of

psychology textbooks sold. How many textbooks of each type were sold?

Answer 1

Explanation:

h and p are the number of history and psych textbooks, respectively.

store sold a total of 411 textbooks in a week.

h + p = 411

The number of history textbooks sold was 69 less than the number of psychology textbooks sold.

h = p - 69

Substitution

(p-69) + p = 411

2p = 411+69

p = 240

h = p-69 = 171

171 history books and 250 psych books