Probes

Expert replies

Aman verma: Master | Next Rank: 500 Posts; Posts: 304; Joined: Wed Jan 27, 2010 8:35 amFollowed by: 3 members; Location: International Space Station; Thanked: 11 times

by Aman verma » Tue Sep 27, 2011 5:25 am

Q: Robot Corporation US, manufactures robotic Probes and they test their robotic probes across various states. Once, early morning Probe A was sent from DC. to NY. Two hours later Probe B was sent from DC. to NY. However both the Probes reach NY simultaneously. If Probe A was sent from DC. and Probe B was sent from NY at the same time and travelled towards each other they would have meet in 1 Hour 20 Minutes. Find the time taken by Probe A to travel from DC. to NY.

a) 2h

b) 3h

c) 4h

d) 5h

e) 6h

Last edited by Aman verma on Tue Sep 27, 2011 7:49 am, edited 1 time in total.

800. Arjun's-Bird-Eye

Source: Beat The GMAT — Problem Solving | Tue Sep 27, 2011 5:25 am

user123321: Master | Next Rank: 500 Posts; Posts: 385; Joined: Fri Sep 23, 2011 9:02 pmFollowed by: 6 members; Thanked: 62 times

by user123321 » Tue Sep 27, 2011 5:56 am

P-----------Q
x

speed of A= x/t(say t is time taken for A to travel from P to Q)
speed of B= x/(t-2)

based on second clue..
(speed of A)*(1+1/3)+(speed of B)*(1+1/3) = x
substituting above speeds we get x variable cancelled on both sides and after solving a bit more we get...
1/t+1/(t-2) = 3/4

clearly x should be 4 for above equation to be true.

user123321

gmatclubmember: Master | Next Rank: 500 Posts; Posts: 158; Joined: Sat Sep 03, 2011 10:31 amFollowed by: 2 members; Thanked: 29 times

by gmatclubmember » Tue Sep 27, 2011 6:05 am

let A take time t to reach NY then B take time (t-2) in hours.
distance b/w NY and DC 'd'.
Speed of A = d/t and speed of B = d/(t-2).

If they meet after 80/60 hours then in that time they both have covered distance d.
80/60*d/t +80/60 *d/(t-2) = d.
Solving we get t = 4 hours.

Cheers
Ami/-

Aman verma: Master | Next Rank: 500 Posts; Posts: 304; Joined: Wed Jan 27, 2010 8:35 amFollowed by: 3 members; Location: International Space Station; Thanked: 11 times

by Aman verma » Tue Sep 27, 2011 7:56 am

OA[spoiler]c)[/spoiler]

800. Arjun's-Bird-Eye

Featured schoolRound 2 closes Jan 7, 2027 53 days left

Chicago Booth

Since 1982, 10 Booth faculty members have received the Nobel Prize in Economic Sciences, more than any other business school.

#3
U.S. News rank: $175,000
Median base salary: 670
Average GMAT Focus: 635
Students in the class

Apply to Booth Visit chicagobooth.edu See the full profile

Photo: Warren LeMay, CC BY-SA 2.0

GMAT Course Reviews

563 reviews

1168 reviews

431 reviews

359 reviews

147 reviews

5/5

5 Star (563 Reviews)

"Target Test Prep is the closest to the official version of the GMAT exam, about 99% accuracy in terms of the quality and quantity of information. The course has excellently created singular sets of focused lessons and tests for every possible topic that one could come across in the official GMAT exam."

"The TTP course maximizes the efficiency of the time you spend studying. It will take time and effort but I could almost guarantee that if you complete the course exactly as it is laid out you will get an amazing score. They also have a very responsive team willing to help with any questions you might have."

"TTP has two things that I think no other test prep company offers: A teaching approach that reinforces understanding and an attitude that will give you the mental preparedness needed to succeed on the test. TTP gives you a deep understanding of the concept you need to know while teaching you how to think."

Write a Review