Question

A textbook store sold a combined total of 475 sociology and history textbooks in a week. The number of history textbooks sold was 83 less than the number of sociology textbooks sold. How many textbooks of each type were sold?

Answer 1

Let the number of Sociology books = y; the number of History books = x

⇒ x + y = 475 (2)
also since the number of history books sold was 83 less than sociology,
then x = y - 83 (1)

BY substituting (1) into (2)
⇒ (y - 83) + y = 475
2y = 475 + 83
y = (558 ÷ 2)
y = 279

⇒ x = 279 - 83
x = 196

∴ Number of History books is 196 & number of Sociology books is 279.