Total books = 260. Novels : Textbooks = 8 : 5.<br><br>
[[model:questions/solutions/q10504.png]]<br><br>
Total units = 8 + 5 = 13 units<br>
&bull; 13 units → 260<br>
&bull; 1 unit → 260 ÷ 13 = 20<br>
&bull; Novels = 8 units = 8 × 20 = 160<br>
&bull; Textbooks = 5 units = 5 × 20 = 100<br><br>
Now find hardcover in each group:<br>
Novels &mdash; paperback : hardcover = 7 : 1, so hardcover novels = \( \frac{1}{8} \) × 160 = 20<br>
Textbooks &mdash; paperback : hardcover = 2 : 3, so hardcover texts = \( \frac{3}{5} \) × 100 = 60<br><br>
Total hardcover books = 20 + 60 = 80<br>
Check: Paperback novels = 140, paperback texts = 40. 20 + 60 + 140 + 40 = 260. ✓<br><br>
Final Answer: 80