A certain dam regulates the volume of water that flows . . .

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A certain dam regulates the volume of water that flows through its floodgates by reducing the area through which water can pass. Does the dam normally allow at least 30% of the maximum volume of water that can pass to flow through?

(1) The maximum volume of water that can pass through the floodgates is three times the volume which is normally allowed to flow through.

(2) The area through which water is allowed to pass is normally less than one third of maximum.

The OA is the option A.

I need some help here. Experts, can you give me an explanation here? Please. I would be thankful.

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by Jay@ManhattanReview » Tue Jan 16, 2018 11:27 pm
Vincen wrote:A certain dam regulates the volume of water that flows through its floodgates by reducing the area through which water can pass. Does the dam normally allow at least 30% of the maximum volume of water that can pass to flow through?

(1) The maximum volume of water that can pass through the floodgates is three times the volume which is normally allowed to flow through.

(2) The area through which water is allowed to pass is normally less than one third of maximum.

The OA is the option A.

I need some help here. Experts, can you give me an explanation here? Please. I would be thankful.
What's the source of the question? Information from the statements is inconsistent.

We have to determine whether the normal rate of flow ≥ 30% of the maximum rate of flow.

(1) The maximum volume of water that can pass through the floodgates is three times the volume which is normally allowed to flow through.

=> The maximum rate of flow = 3*The normal rate of flow

Thus, the normal rate of flow = The maximum rate of flow / 3 = 33.33% of the maximum rate of flow > 30% of the maximum rate of flow. Sufficient.

(2) The area through which water is allowed to pass is normally less than one-third of maximum.

=> The normal rate of flow < 1/3 of the maximum rate of flow

The normal rate of flow < 33.33% of the maximum rate of flow

Case 1: If 30% of the maximum rate of flow ≤ The normal rate of flow < 33.33% of the maximum rate of flow, the answer is Yes.

Case 2: If the normal rate of flow < 30% of the maximum rate of flow, the answer is No. No unique answer.

Though the correct answer is A, the question has a flaw. While the Statement 1 states that the normal rate of flow is equal to 33.33% of the maximum rate of flow, the Statement 2 states that the normal rate of flow is less than 33.33% of the maximum rate of flow. How can both the information holistically present a situation correctly?

Had the Statement 2 been, "The area through which water is allowed to pass is normally less than equal to one-third of maximum,'' the inconsistency would cease to exist.

Hope this helps!

-Jay
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