Answer :
We have been given that a librarian noticed that 60% of seventh graders checked out fantasy books. We are asked to find the number of seventh graders from 240 seventh graders, who would checkout fantasy books.
To solve our given problem, we need to find 60% of 240.
[tex]\text{Seventh graders, who would checkout fantasy books}=240\times \frac{60}{100}[/tex]
[tex]\text{Seventh graders, who would checkout fantasy books}=240\times 0.60[/tex]
[tex]\text{Seventh graders, who would checkout fantasy books}=144[/tex]
Therefore, 144 seventh graders would checkout fantasy books.