(1 – 1.25)N = 1

[boomgoesthegmat]

If (1 - 1.25)N = 1, then N =
A) -400
B) -140
C) -4
D) 4
E) 400

C

[Matt@VeritasPrep]

N - 1.25N = 1

-.25N = 1

-N = 4

N = -4

[Brent@GMATPrepNow]

If (1 - 1.25)N = 1, then N =
A) -400
B) -140
C) -4
D) 4
E) 400

Matt's solution makes more sense, but here's another approach (for kicks):
Given: (1 - 1.25)N = 1
Divide both sides by N to get: 1 - 1.25 = 1/N
Evaluate: -0.25 = 1/N
Rewrite as fraction: -1/4 = 1/N
Orrrrr: 1/(-4) = 1/N
So, N must equal -4

Answer: C

Cheers,
Brent

[Scott@TargetTestPrep]

If (1 - 1.25)N = 1, then N =
A) -400
B) -140
C) -4
D) 4
E) 400

We can simplify the given equation:

(1 - 1.25)N = 1

-0.25N = 1

N = 1/(-0.25)

N = -4

Answer: C

[[email protected]]

Hi All,

Most Test Takers would agree that this prompt is one of the easier OG 'math' questions that they've seen - and from the various solutions provided, you can see that the 'work' needed to answer this question is fairly straight-forward and - in certain terms - 'low level.' As such, I won't rehash any of that work here. Instead, I want to point out that you WILL see questions on Test Day that you consider "easy" - so don't become concerned about seeing those questions when they appear. Everyone sees a few "gimmes" regardless of your ability level - and to maximize your score you MUST get ALL of those easy questions correct. Thus, make sure to write everything on your pad, do the proper work to get the correct answer and pick up those easy points.

GMAT assassins aren't born, they're made,
Rich