Answer:
The librarian can order up to 23 books.
From the estimate, 23 books costs;

Adding the cost of shipping;

The total cost is less than $100 which makes it reasonable.
Step-by-step explanation:
Given that The school librarian has $100 to spend on some books for the school.
And Each copy costs $3.95. Shipping for the books will be $6.95.
We can write the inequality to describe the situation as;
Let x represent the number of books she can buy

solving for x;

the highest possible integer in the solution is;

Therefore, The librarian can order up to 23 books.
From the estimate, 23 books costs;

Adding the cost of shipping;

The total cost is less than $100 which makes it reasonable.