Of all the computers owned by Company X, 1/3 were manufactured before

Question

Of all the computers owned by Company X, \(\frac{1}{3}\) were manufactured before 1995. If \(\frac{1}{4}\) of the computers manufactured before 1995 were replaced with new computers, the percent of Company X's computer's manufactured before 1995 would be?

A. \(8\frac{1}{3}\)%

B. \(12.5\)%

C. \(20\)%

D. \(25\)%

E. \(27\frac{1}{3}\)

Show Answer

Official Answer

D

A.  8\frac{1}{3} %

B.  12.5 %

C.  20 %

D.  25 %

E.  27\frac{1}{3}

IanStewart · Answer

You can just imagine having 36 computers in total. Then 12 were made before 1995. We replace 1/4, or three, of those with new computers. That leaves us with 9 old computers, and the total remains 36, so the answer is 9/36 = 25%.

K5 · Answer

How did people get answer A?

AllisonBell · Answer

Good question! One way to arrive at (incorrect) answer choice (A) is to multiply 1⁄3 x 1⁄4. This is actually a common wrong answer pattern on the GMAT, and a good one to be aware for situations when you need to guess. Often, at least one wrong answer choice will reflect the result of a simple arithmetic operation between the numbers in the problem (for example, multiplying the numbers together or adding them). That tends to be wrong, since most GMAT Quant problems involve multiple steps.

For more GMAT practice problems and explanations, check out ManhattanPrep’s   Free GMAT Starter Kit & QBank  .

Of all the computers owned by Company X, 1/3 were manufactured before

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Problem Solving (PS) Questions

Of all the computers owned by Company X, 1/3 were manufactured before

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards