Ms.Keller is speed reading a book that has 342 pages, she has already completed 300 of them and can read 2 pages per minute. The question is asking how long it'll take her to finish this book.
So we know the vital information that Keller reads two pages per minute and she only has 42 pages left of the book, this is all we need to answer the question.
All we need to do is divide 42 by 2 :
42 / 2
21
Therefore, it'll takeMs.Keller 21 minutes to finish the book at the constant speed
