Amalia can read 4 pages of her book in 2 minutes. How many minutes will it take her to read 18 pages of her book? Think carefully first, then make a decision:
Amalia can read 1 page in 2 / 4 = 0.5 minutes. Hence, she can read 18 pages in 18 x 0.5 minutes = 9 minutes. So, the answer is 9.