Harriet wants to put up fencing around three sides of her

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by Brent@GMATPrepNow » Tue Oct 08, 2019 7:55 am
swerve wrote:Harriet wants to put up fencing around three sides of her rectangular yard and leave one side of 20 feet unfenced. If the yard has an area of 680 square feet, how many feet of fencing does she need?

A. 34
B. 40
C. 68
D. 88
E. 102

The OA is D

Source: Official Guide
Here's a sketch of what we're dealing with:
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Given: area of the rectangle = 680

Area = (base)(height) = (x)(20) = 20x

So: 20x = 680
Solve: x = 680/20 = 34

We now have:
Image

Perimeter = 34 + 34 + 20 = 88

Answer: D

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by Scott@TargetTestPrep » Fri Oct 11, 2019 2:37 pm
swerve wrote:Harriet wants to put up fencing around three sides of her rectangular yard and leave one side of 20 feet unfenced. If the yard has an area of 680 square feet, how many feet of fencing does she need?

A. 34
B. 40
C. 68
D. 88
E. 102

The OA is D

Source: Official Guide
Since the yard is a rectangle and one side is 20, which we can call the length, then the width (w) is:

680 = 20w

34 = w

Thus, she needs 34 + 34 + 20 = 88 feet of fencing.

Answer: D

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