Question: 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? Think carefully first, then make a decision:
The total cost for the sand is 500 * 10 = $5000. Since each lorry was carrying 10 tons of sand, the twenty lorries carried 20 * 10 = 200 tons. At $40 per ton, Mr. Zander paid 200 * $40 = $8000 for the sand that was delivered to his construction site. Altogether, Mr. Zander paid $8000 + $5000 = $13000 for the delivered construction materials. So the answer is 13000.