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?
Amalia can read 1 page in 2/4 = 0.5 minutes.
Hence, she can read 18 pages in 18 x 0.5 minutes = 
<gadget id="calculator">18*0.5</gadget>
<output>9</output>
9 minutes.

<result>9</result>