Brent@GMATPrepNow wrote:Moe is 20% taller than Jane. If Moe is x inches tall, which of the following represents Jane's height in inches?
A) 4x/5
B) 5x/6
C) 2x/3
D) 5x/4
E) 6x/5

I created this question to highlight a common misconception that goes something like this:
If Moe is 20% taller then Jane, then Jane must be 20% shorter than Moe. If you have this misconception, then you will incorrectly choose A as your answer.
For more on this common misconception, read https://www.gmatprepnow.com/articles/co ... 93-part-ii

Moe is 20% taller than Jane.
Let J = Jane's height (in inches)
So, 1.2J = Moe's height

Moe is x inches tall.
We just learned that 1.2J = Moe's height
So, we can write: 1.2J = x
Since 1.2 = 6/5, we can rewrite the equation as follows: (6/5)J = x

Which of the following represents Jane's height in inches?
Solve the equation (6/5)J = x for J
Multiply both sides of the above equation by 5/6 to get: J = (5/6)(x)
Simplify: J = 5x/6

Answer: B

Cheers,
Brent