John plays at the arcade for 3 hours.  He uses $.50 for every 6 minutes.  How much money did he spend, in dollars?
He was at the arcade for 3*60=
<gadget id="calculator">3*60</gadget>
<output>180</output>
180 minutes.
So he put coins in 180/6=
<gadget id="calculator">180/6</gadget>
<output>30</output>
30 times.
That means he spent 30*.5=$
<gadget id="calculator">30*.5</gadget>
<output>15</output>
15.

<result>15</result>