Thursdays With Ron: Percent Multipliers

by Manhattan Prep, Jul 29, 2010

Every other Thursday, our instructor Ron Purewal (known on the Beat The GMAT forums as lunarpower) hosts a free study hall session, called Thursdays with Ron, where anyone can submit questions ahead of time and attend. Ron chooses a few themes from the questions he gets and goes over strategies for them.

In this recording, Ron goes over Percent Multipliers:

Heres an outline of what Ron covers, with the minute markers. Make sure to watch the video, though, so that youre able to follow along!

• 0:23 Slow way to raise x by 15% - Ron tells us the way that we shouldnt figure this out.
• 1:00 Whats the fast way to raise x by 15%? Simply multiply by 1.15.
• 2:09 What about raising x by 150%? This gets tricky.
• 3:50 Whats the quickest way to decrease x by 15%? Multiply by 0.85.
• 5:45 How would you write x has been increased by 10% and the result has again been increased by 10%?
• 7:33 How to increase x by P% and how to decrease x by P%

If you want to view recordings of past Thursdays with Ron or submit questions for the next live session, which takes place on August 5th you can do so here.