John can read a book 60% faster than his brother.  If his brother takes 8 hours to read a book, how long would it take John to read 3 books?
Reading 60% faster means John's brother takes 1+.6=1.6 times as long as John to read.
So John reads a book in 8/1.6=
<gadget id="calculator">8/1.6</gadget>
<output>5</output>
5 hours.
So it would take John 5*3=
<gadget id="calculator">5*3</gadget>
<output>15</output>
15 hours to read 3 books.

<result>15</result>