GMAT Prep From Platinum GMAT

GMAT Prep Materials

Announcement

Check out our latest blog post about The Best GMAT Books for Studying on Your Own.

About Us

Platinum GMAT Prep provides the best GMAT preparation materials available anywhere, enabling individuals to master the GMAT and gain admission to any MBA program. We also provide hundreds of pages of free GMAT prep content, including practice questions, study guides, and test overviews.

rss GMAT Practice Question (One of Hundreds)
A computer has three hard-drives; the smallest and largest hard-drives account for 25 and 45 percent of the total storage space on the computer, respectively; due to a catastrophic error, the largest hard-drive lost approximately 22% of its storage space; after this error, the hard drive that was originally the second largest accounts for approximately what percent of the total hard-drive space on the reduced computer?
Correct Answer: B
Use the following equation: 25% + 45% + medium hard drive = 100%
  1. Since there are only three hard drives and these account for 100% of the space on the computer, you can write the following equation:
    (Smallest Hard Drive) + (Medium Hard Drive) + (Large Hard Drive) = 100%
    25% + (Medium Hard Drive) + 45% = 100%
  2. You now know the size of the medium hard drive:
    (Medium Hard Drive) = 30%
  3. If the largest hard-drive lost approximately 22% of its storage space, it now accounts for (1-.22)(.45) = .351 or 35.1% of the old total space.
  4. You can now find what percent of the total hard-drive space the second largest hard drive accounts for:
    = (Drive Originally 2nd Largest) / (New Total Drive Space)
    = 30%/(35.1%+25% + 30%) = 30%/90% = ~ 33%
  5. If the concept of manipulating and dividing percents throws you off, this is an excellent problem to pick numbers on. Simply let the percents be actual hard-drive space. In other words, set the total hard drive space to be 100GB. Then, the smallest hard-drive is 25GB, the medium hard-drive is 30GB, and the largest is 45GB. After the largest shrinks by 22%, it is now 45*(1-.22) = 35GB. So, the reduced hard drive is 25+30+35 = 90GB and the second largest hard drive is 30GB/90GB = 33%.