Source: Official Guide for GMAT Review 2016 Problem Solving; #160

1

The price of lunch for 15 people

The price of lunch for 15 people was $207.00, including a 15 percent gratuity for service. What was the average price per person, EXCLUDING the gratuity?

2 Explanations

1

Ricardo Martinez

Would be useful if you continued showing the process in the long division

Apr 21, 2018 • Comment

Sam Kinsman, Magoosh Tutor

Hi Ricardo,

The part of the long division process that wasn't fully explained was how we know that 1.15 goes into 92 exactly 80 times. So I'm guessing that this is the part you are referring to!

Well, during long division, sometimes it is helpful to "guess and check." For example, you know that since 1.15 is slightly bigger than 1, the result of 92/1.15 has to be a bit less than 92. So we could start by trying 70. We can do that multiplication by hand, to get 80.5. Ok, we know we need a bigger number - so we try 75. 75*1.15=86.25. Still too small. So try 80*1.15, and you get exactly 92 - so that's the number we need!

For more on long division, you might want to check out some of the videos here https://www.khanacademy.org/tag/long-division

Apr 23, 2018 • Reply

1

Gravatar Mike McGarry, Magoosh Tutor

Aug 17, 2015 • Comment

Add Your Explanation

You must have a Magoosh account in order to leave an explanation.

Learn More About Magoosh

Official GMAT Material

Official Guide for GMAT Review 2016

Official Guide for the GMAT 13th Ed.

Official Guide for the GMAT 2015 14th Ed.

Official Guide for the GMAT 12th Ed.

Revised GRE PDF 2nd Ed.


Section 5.3 Problem Solving

Improve Your Score

Magoosh GMAT is an affordable online course for studying the GMAT.

Learn More About Magoosh

Share Post

Email

Facebook