On a construction site, the Laker cement factory provided 500 bags of cement sold to Mr. Zander at $10 per bag. Mr. Zander also received twenty lorries of construction sand, each carrying 10 tons of sand, sold at $40 per ton. How much money did Mr. Zander pay for these construction materials?
The total cost for the sand is 500*10 = $
<gadget id="calculator">500*10</gadget>
<output>5_000</output>
5000.
Since each lorry was carrying 10 tons of sand, the twenty lorries carried 20*10 = 
<gadget id="calculator">20*10</gadget>
<output>200</output>
200 tons.
At $40 per ton, Mr. Zander paid 200*$40 = $
<gadget id="calculator">200*40</gadget>
<output>8_000</output>
8000 for the sand that was delivered to his construction site.
Altogether, Mr. Zander paid $8000+$5000 = $
<gadget id="calculator">8000+5000</gadget>
<output>13_000</output>
13000 for the delivered construction materials.

<result>13_000</result>