65% percentile problem Rate Type

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oquiella: Master | Next Rank: 500 Posts; Posts: 164; Joined: Tue May 12, 2015 9:06 am; Thanked: 3 times

65% percentile problem Rate Type

by oquiella » Sat Nov 07, 2015 7:11 am

Nicole cycles at a constant rate of 20 kilometers per hour, and is passed by Jessica, who cycles at a constant rate of 30 kilometers per hour. If Jessica cycles at her constant rate for x minutes after passing Nicole, then stops to wait for her, how many minutes will Jessica have to wait for Nicole to catch up to her?

x minutes
x2 minutes
2x3 minutes
3x2 minutes
2x minutes

What is the key when solving problems with the same variables?

Quote

Source: Beat The GMAT — Problem Solving | Sat Nov 07, 2015 7:11 am

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by [email protected] » Sat Nov 07, 2015 11:22 am

Hi oquiella,

These types of questions can often be solved by TESTing VALUES. I'm going to give you some hints so that you can re-attempt the question in that way.

1) 20 km/hour and 30k/hour are nice round numbers. Since the prompt refers to X MINUTES, you should choose an X that will allow you to keep your calculations simple. Since we're talking about 'fractions of an hour', you might want to try 10, 20, 30 or 60 for X.

2) Using whatever number you choose for X, calculate how far ahead Jessica gets.

3) Once you have that distance, calculate how long it takes Nicole to 'catch up'

4) Using your original value for X, find the answer that matches.

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

Contact Rich at [email protected]