John has just turned 39.  3 years ago, he was twice as old as James will be in 6 years.  If James' older brother is 4 years older than James, how old is James' older brother?
John was 39-3=
<gadget id="calculator">39-3</gadget>
<output>36</output>
36 years old 3 years ago.
So that means in 6 years James will be 36/2=
<gadget id="calculator">36/2</gadget>
<output>18</output>
18 years old.
So right now James is 18-6=
<gadget id="calculator">18-6</gadget>
<output>12</output>
12 years old.
So James's older brother is 12+4=
<gadget id="calculator">12+4</gadget>
<output>16</output>
16 years old.

<result>16</result>