GRE Quantitative Practice Questions — Standard Multiple-choice Format

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Question 5

How many complete tanks of water, each with a capacity of 3 cubic meters, are needed to fill an empty cylindrical tank whose height is 3 meters and whose base has a radius of 2 meters?

Note: The value of pi (π) ≈ 3.14.

(A)  12
(B)  13
(C)  14
(D)  15
(E)  16

Answer and Analysis

The correct response is (B). The volume of the cylindrical tank is (h)(πr2), where h is the cylinder's height and r is its radius:

    V = (h)(πr2) = (3)(4)π = 12π
The value of π is given as approximately 3.14. Accordingly, the large tank's volume is between 37 and 38 cubic meters. With a volume of 3 cubic meters each, 13 smaller tanks of water are needed to fill the larger tank in its entirety. (12 tanks of water amount to 36 cubic meters, which is not enough.)