Answer:
The number of pages they have read is 272 pages.
[tex]n=272\text{ pages}[/tex]Explanation:
Given;
The class has read 68% of the book.
If the total number of pages is 400.
Then;
let n represent the number of pages they have read;
[tex]\begin{gathered} n=68\text{\% of 400} \\ n=\frac{68}{100}\times400 \\ n=272\text{ pages} \end{gathered}[/tex]Therefore, the number of pages they have read is 272 pages.