Trevor's older brother was twice his age 20 years ago. How old was Trevor a decade ago if his brother is now 32 years old?
If Trevor's brother is 32 years old today then 20 years ago he was = 32-20 = 
<gadget id="calculator">32-20</gadget>
<output>12</output>
12 years old.
If Trevor's brother was 12 years old and he was twice Trevor's age, then Trevor was 12/2 = 
<gadget id="calculator">12/2</gadget>
<output>6</output>
6 years old.
If Trevor was 6 years old 20 years ago, then he must be 6 + 20 = 
<gadget id="calculator">6+20</gadget>
<output>26</output>
26 years old today.
If Trevor is 26 years old today then a decade ago he must have been 26-10 = 
<gadget id="calculator">26-10</gadget>
<output>16</output>
16 years old.

<result>16</result>