An irregular plot of land is surrounded by four straight segments of fence of meter lengths

This topic has expert replies
Moderator
Posts: 7187
Joined: Thu Sep 07, 2017 4:43 pm
Followed by:23 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

An irregular plot of land is surrounded by four straight segments of fence of meter lengths (5x + 5), (5x + 5), (3x + 10) and 2x. Is the total length of fence greater than 70 meters?

(1) The average (arithmetic mean) fence segment length is less than 25 meters.

(2) The largest fence segment is three times the length of the smallest fence segment.


OA B

Source: Princeton Review
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 3008
Joined: Mon Aug 22, 2016 6:19 am
Location: Grand Central / New York
Thanked: 470 times
Followed by:34 members

Timer

00:00

Your Answer

A

B

C

D

E

Global Stats

BTGmoderatorDC wrote:
Thu Apr 16, 2020 5:55 pm
An irregular plot of land is surrounded by four straight segments of fence of meter lengths (5x + 5), (5x + 5), (3x + 10) and 2x. Is the total length of fence greater than 70 meters?

(1) The average (arithmetic mean) fence segment length is less than 25 meters.

(2) The largest fence segment is three times the length of the smallest fence segment.

OA B

Source: Princeton Review
From the information, we know that the total length of the fence

= (5x + 5) + (5x + 5) + (3x + 10) + 2x = 17x + 20

So, we have to ascertain whether 17x = 20 > 70 => x > 2.9...

Question rephrased; Is x > 2.9...?

Let's take each statement one by one.

(1) The average (arithmetic mean) fence segment length is less than 25 meters.

[(5x + 5) + (5x + 5) + (3x + 10) + 2x]/5 < 25

x < 4.7...

Case 1: If 4,7.. > x > 2.99, the answer is yes.
Case 2: If 2.9.. > x, the answer is no.

No unique answer. Insufficient.

(2) The largest fence segment is three times the length of the smallest fence segment.

We can be certain that the length of the smallest fence is 2x meters; however, the length of the largest fence can be (3x + 10) or (5x + 5).

Case 1: Say the length of the largest fence is (3x + 10).

=> 3x + 10 = 3*2x => x = 3.33 > 2.99. The answer is yes.

Case 2: Say the length of the largest fence is (5x + 5).

=> 5x + 5 = 3*2x => x = 5 > 2.99. The answer is yes.

unique answer. Sufficient.

The correct answer: B

Hope this helps!

-Jay
_________________
Manhattan Review GMAT Prep

Locations: Manhattan Review Warangal | Hyderabad | GRE Prep Himayatnagar | Dilsukhnagar GRE Coaching | and many more...

Schedule your free consultation with an experienced GMAT Prep Advisor! Click here.