A water district charges a minimum of ₱200 for the first 10 cubic metres and ₱35 for each additional cubic metre. What is the bill for 18 cubic metres?
Correct answer: B. ₱480
The first 10 m³ cost ₱200. The remaining 8 m³ cost 8 × ₱35 = ₱280. Total = ₱480. Charging ₱35 for all 18 m³ on top of the minimum is a common error.
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