John buys dinner plates and silverware.  The silverware cost $20.  The dinner plates cost 50% as much as the silverware.  How much did he pay for everything?
The dinner plates cost 20*.5=$
<gadget id="calculator">20*.5</gadget>
<output>10</output>
10.
So he paid 10+20=$
<gadget id="calculator">10+20</gadget>
<output>30</output>
30.

<result>30</result>