James paints a 20 ft by 15 ft mural.  It takes him 20 minutes to paint 1 square foot and he charges $150 per hour.  How much does he charge to paint the mural?
The mural is 20*15=
<gadget id="calculator">20*15</gadget>
<output>300</output>
300 square feet.
So it takes him 300*20=
<gadget id="calculator">300*20</gadget>
<output>6_000</output>
6000 minutes.
So he paints it in 6000/60=
<gadget id="calculator">6000/60</gadget>
<output>100</output>
100 hours.
That means he charges 100*150=$
<gadget id="calculator">100*150</gadget>
<output>15_000</output>
15000.

<result>15_000</result>