Given the following reasoning and answer, what was the question? Grace can read 200 / 20 = 10 pages in 1 hour. So she can finish a 250 - page book in 250 / 10 = 25 hours.
 The answer: 25
The question Grace can read a 200-page book in 20 hours. How long would it take her to finish reading a 250-page book at this constant rate?