Question

A textbook store sold a combined total of 217 sociology and history textbooks in a week. The number of history textbooks sold was 77 less than the number of

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

Answer 1

there were 246 chemistry textbooks and 169 psychology textbooks sold

Explanation:

Let

c = the number of chemistry textbooks sold

p = the number of psychology textbooks sold

a textbook store sold a combined total 415 chemistry and psychology textbooks in a week

c + p = 415

the number of chemistry textbooks sold was 77 more than the number of psychology textbooks sold

c = 77 + p

by solving the system of equations

c + p = 415

c = 77 + p

we find

c = 246 chemistry textbooks

p = 169 psychology textbooks