Question

The teaching volume of story books in the book corner is three times that of picture books. There are 18 more story books than picture books. How many story books are there in the book corner?

Answer 1

$s=3p$

$s=p+18$

So, $3p=p+18\to p=9, s=9+18=27.$

There are $s+p=27+9=36$ books in the book corner.