To find the number of paperback books that weigh 25 pounds when each book weighs 1/3 pounds, you can set up a proportion.
Let's let "x" represent the number of paperback books.
The proportion can be set up as:
1/3 pounds per book = 25 pounds / x books
To solve for "x", you can cross-multiply:
1 × x = 3 × 25
x = 75
Therefore, 75 paperback books together would weigh 25 pounds.