GMATinsight wrote:
Bunuel wrote:
A room of height 10 feet and equal length and width has a cylindrical pillar exactly in the center, what is the volume of the room excluding the space occupied by the pillar?
(1) The farthest horizontal distance from any point in the room to the pillar is 10 feet.
(2) The area occupied by the base of the pillar is 4π feet.
Question : Volume of cubical room = Volume of Cylinder \(= a^3 - πr^2h =\)?Also, Height of the pillar = a
Statement 1: The farthest horizontal distance from any point in the room to the pillar is 10 feeti.e. \((1/2)*(a√2-2r) = 10\)
NOT SUFFICIENT
Statement 2: The area occupied by the base of the pillar is 4π feeti.e. \(πr^2 = 4π\)
i.e. \(r = 2\)
btu a is still unknown hence
NOT SUFFICIENT
Combining the two statementswe can substitute \(r=2\) in \((1/2)*(a√2-2r) = 10\) to calculate value of a hence
SUFFICIENT
ANswer: option C
Dear
GMATinsight,
Please can you explain statement 1 , what do we mean by "The farthest horizontal distance from any point in the room to the pillar is 10 feet."
Also how do we know that the room is a cube ? When the question says height 10 and equal length and width this can be interpreted two ways :
First: Height = 10 = Length = width
Second: A room has height 10 , whose length and width are equal.
Hope you can help, thank you.
Farthest horizontal distance from pillar = distance between a corner of room and pillar = Half of the diagonal of the square on ground
We have not assumed room is a cube... Only the length and width are equal as given in question
Second: A room has height 10 , whose length and width are equal.
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