Question

A textbook store sold a combined total of 256 sociology and blology textbooks in a week. The number of sociology textbooks sold was three times the number of
blology textbooks sold. How many textbooks of each type were sold?
Number of sociology textbooks sold: ?.
Number of biology textbooks sold: ?.

1. thugiang
The number of sociology textbooks sold is 192, and the number of biology textbooks sold is 64.

### What is a linear equation?

It is defined as the relation between two variables, if we plot the graph of the linear equation we will get a straight line.
If in the linear equation, one variable is present, then the equation is known as the linear equation in one variable.
It is given that:
A textbook store sold a combined total of 256 sociology and biology textbooks in a week.
Let x be the number of sociology textbooks sold
Let y be the number of biology textbooks sold
x + y = 256
x = 3y
Using substitution method:
3y + y = 256
4y = 256
y = 256/4
y = 64
x = 192
Thus, the number of sociology textbooks sold is 192, and the number of biology textbooks sold is 64.