Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 25 May 2013, 12:41

# From MitDavidDv: A 700-800 Level GMAT Quant Question

Author Message
TAGS:
Manager
Joined: 28 Jan 2011
Posts: 78
Location: Tennessee
Schools: Belmont University
Followers: 1

Kudos [?]: 6 [1] , given: 54

From MitDavidDv: A 700-800 Level GMAT Quant Question [#permalink]  29 Mar 2011, 14:01
1
KUDOS
00:00

Question Stats:

47% (03:28) correct 52% (03:29) wrong based on 1 sessions
A cylindrical tank has a base with a circumference of 4sqrt^(pi * sqrt^3) meters and an equilateral triangle painted on the interior side of the base. If a stone is dropped inside the tank and the probability of the stone hitting the portion of the base outside the triangle is 3/4, what is the length of a side of the triangle?

a.) Sqrt^(2*sqrt^6)

b.) Sqrt^(6*sqrt^6)/2

c.) Sqrt^(2*sqrt^3)

d.) Sqrt^3

e.) 2
[Reveal] Spoiler: OA
Retired Moderator
Joined: 02 Sep 2010
Posts: 815
Location: London
Followers: 56

Kudos [?]: 302 [2] , given: 25

Re: From MitDavidDv: A 700-800 Level GMAT Quant Question [#permalink]  29 Mar 2011, 14:10
2
KUDOS
MitDavidDv wrote:
A cylindrical tank has a base with a circumference of 4sqrt^(pi * sqrt^3) meters and an equilateral triangle painted on the interior side of the base. If a stone is dropped inside the tank and the probability of the stone hitting the portion of the base outside the triangle is 3/4, what is the length of a side of the triangle?

a.) Sqrt^(2*sqrt^6)

b.) Sqrt^(6*sqrt^6)/2

c.) Sqrt^(2*sqrt^3)

d.) Sqrt^3

e.) 2

Let the radius of the base be r
Right so the circumference = 4 \sqrt{\pi * \sqrt{3}}=2 \pi r
Simplifying we get r = \frac{4\sqrt{3}}{\sqrt{\pi}}
Area of base = \pi r^2 = 4 \sqrt{3}

Let the side of the triangle be x, the area of the triangle is \frac{\sqrt{3}x^2}{4}

Probably that the stone will fall inside the triangle = 1 - (3/4) = (1/4) = (Area of triangle)/(Area of base)

Substituting the areas calculated above : \frac{\frac{\sqrt{3}x^2}{4}}{4\sqrt{3}} = \frac{1}{4}
Which simplifies to give : x^2=4

Hence x=2

_________________
Re: From MitDavidDv: A 700-800 Level GMAT Quant Question   [#permalink] 29 Mar 2011, 14:10
Similar topics Replies Last post
Similar
Topics:
1 From MitDavidDv: GMAT Quant-Math Question 5 07 Apr 2011, 14:20
2 From MitDavidDv: GMAT Quant-Math Question #2 5 07 Apr 2011, 15:43
1 From MitDavidDv: Test Day Question 2 20 May 2011, 10:46
2 From MitDavidDv: GMAT Preparation Question 2 01 Jun 2011, 14:19
1 From MitDavidDv: Preparation For Quant and Verbal Question 1 09 Jun 2011, 10:20
Display posts from previous: Sort by