boomgoesthegmat wrote:A rectangular garden is to be twice as long as it is wide. If 360 yards of fencing, including the gate, will completely enclose the garden, what will be the length of the garden, in yards?
A) 120
B) 140
C) 160
D) 180
E) 200
A
Normally, I'd use the 1-variable approach that Matt used. However, I'll also show how we can also use 2 variables.
Let W = the width of the rectangle
Let L = the length of the rectangle
A rectangular garden is to be twice as long as it is wide.
So, we get:
L = 2W
360 yards of fencing, including the gate, will completely enclose the garden
In other words, the perimeter is 360.
So, we can write: L + L + W + W = 360
Simplify to get:
2L + 2W = 360
So, we have the following system of 2 equations with 2 unknowns:
L = 2W
2L + 2W = 360
We can take 2W in the bottom equation and replace it with L to get: 2L + L = 360
Simplify: 3L = 360
Solve: L = 120
Answer:
A
Related Resources
The following videos cover the concepts/strategies that are useful for answering this question:
- Assigning variables:
https://www.gmatprepnow.com/module/gmat ... /video/902
- Writing equations:
https://www.gmatprepnow.com/module/gmat ... /video/903
- How many variables to assign?:
https://www.gmatprepnow.com/module/gmat ... /video/906
Cheers,
Brent
