Forum Home > GMAT > Quantitative > Problem Solving (PS)
Events & Promotions
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.
Customized
for You
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Jun 0712:00 PM PDT
-01:00 PM PDT
In this GMAT experience talk show, we talk to Tavishi, a young MBA aspirant from India who recently scored 725 in her latest GMAT Focus exam. It’s a 99.9 percentile score on the new GMAT Focus edition and she achieved this feat in her first GMAT attempt.
Jun 0811:00 AM IST
-01:00 PM IST
Attend this session to learn how to Deconstruct arguments, Pre-Think Author’s Assumptions, and apply Negation Test.- Jun 09
11:00 AM IST
-01:00 PM IST
Attend this session to evaluate your current skill level, learn process skills, and solve through tough Arithmetic questions - Jun 11
05:30 AM PDT
-12:00 PM PDT
Register for the GMAT Club Virtual MBA Spotlight fair, the biggest MBA fair of the year. You will have a chance to hear Admissions directors from almost every Top 20 program speak, network with peers, and more.
A cop clocks a motorcyclist speeding down the highway at 90 mph. 2 mi
[#permalink]
25 Apr 2010, 07:09
25 Apr 2010, 07:09
4
Bookmarks
Show timer
00:00
A
B
C
D
E
Difficulty:
(N/A)
Question Stats:
93% (01:31) correct
7%
(00:00)
wrong
based on 47
sessions
A cop clocks a motorcyclist speeding down the highway at 90 mph. 2 minutes later the cop tears off after him averaging a speed of 120mph. At this rate how long will it take for our friendly copper to catch the speeder?
Correct Answer:
Correct Answer:
6 min.
Re: A cop clocks a motorcyclist speeding down the highway at 90 mph. 2 mi
[#permalink]
25 Apr 2010, 08:18
25 Apr 2010, 08:18
3
Kudos
1
Bookmarks
gmatt14 wrote:
A cop clocks a motorcyclist speeding down the highway at 90 mph. 2 minutes later the cop tears off after him averaging a speed of 120mph. At this rate how long will it take for our friendly copper to catch the speeder?
Correct Answer: 6 min.
Any suggestions? Please answer step-wise.
BTW: What would be the least known variable? The cop's distance?
Correct Answer: 6 min.
Any suggestions? Please answer step-wise.
BTW: What would be the least known variable? The cop's distance?
HI,
This can be solved by the concept of relative speed
The cop takes off after the speeding car after 2 minutes.
Distance traveled by the car in 2 minutes = Speed * time = 90 * 2/60 = 3 miles
Now speed of cop = 120 mi/hr
Speed of car = 90 mi/hr
Since both are traveling in the same direction their relative speed = 120 - 90 = 30 mi/hr
Distance difference between 2 = 3mi
So time taken for the cop to catch the car = Difference in distance/ relative speed = 3/30 = 1/10 hr = 6 min
Distance traveled by cop = 120* 6/60 = 12 miles
Distance traveled by the car = 90*(6+2)/60 = 12 miles.
Hope this clears all your doubts
cheers
Silvers
Re: A cop clocks a motorcyclist speeding down the highway at 90 mph. 2 mi
[#permalink]
25 Apr 2010, 08:25
25 Apr 2010, 08:25
1
Bookmarks
gmatt14 wrote:
A cop clocks a motorcyclist speeding down the highway at 90 mph. 2 minutes later the cop tears off after him averaging a speed of 120mph. At this rate how long will it take for our friendly copper to catch the speeder?
Correct Answer: 6 min.
Any suggestions? Please answer step-wise.
BTW: What would be the least known variable? The cop's distance?
Correct Answer: 6 min.
Any suggestions? Please answer step-wise.
BTW: What would be the least known variable? The cop's distance?
One suggestion : please put answers in spoilers.
Solution :
in 2 mis, the motorcyclist goes : 3 miles. [ 90/60 * 2]
relative speed = 120 - 90 = 30 mph
At 30 mph rate, 3 miles will be covered in 60/30 * 3 = 6 minutes.
