Problem
Use the information to answer the question. In a library, 3 out of 4 books are nonfiction. Of the nonfiction books, \( 40 \% \) are biographies. The library has a total of \( 840 \mathrm{~b} \) How many nonfiction books does the library have that are biographies? Enter the answer in the box.
Solution
Step 1 ：\(\frac{3}{4}\times 840 = 630\)
Step 2 ：\(0.40 imes 630 = 252\)
