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?
Let's think step by step below.
25
Grace can read 200 / 20 = 10 pages in 1 hour.

So she can finish a 250 - page book in 250 / 10 = 25 hours.

.

The final answer: 25