Each morning, the school librarians place 560 books on a special book shelf. Each student who visits the library that day takes exactly 3 books from the shelf. Let s be the number of students who visit the library on a particular day. Let b be the number of books left on the shelf at the end of that day. T How many books are left on the shelf the day 87 students visit the library?

Ascientist wants to use a model to present the results of his detailed scientific investigation. why would a model be useful? a )because the model makes the concepts easier to understand b) because the model is easy to put together and to use c) because the model prevents other scientists from asking questions d) because the model requires the audience to pay full attention to it i don't know what to choose because between a and d a is much more likely than d because it only wants to get the attention of the audience. i'm confuse.