Welcome! Check out our free B-School Guides to learn how you compare with other applicants.
Login or Register
 

the train kills him right (I)

This topic has 2 member replies
Bookmark
Previous Topic Next Topic
sanju09 GMAT Instructor
Joined
21 Jan 2009
Posted:
3262 messages
Followed by:
48 members
Thanked:
190 times
GMAT Score:
760
the train kills him right (I) Post Mon Mar 12, 2012 3:37 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    A straight rail subway, which is 8 meter long, has P and Q as its two openings. A man stands inside the subway 3 meter away from the opening P, when he notices a train about to enter the subway from the opening P. If the man, immediately after noticing the train, runs with his maximum speed towards the opening P, the train kills him right at the opening P; and if he immediately runs with his same maximum speed towards the opening Q, the train kills him right at the opening Q. How many times faster had been the train than the man?
    (A) 2.5
    (B) 3
    (C) 3.5
    (D) 4
    (E) 4.5

    _________________
    The laws of nature are but the mathematical thoughts of God. ~Euclid

    Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
    killer1387 GMAT Destroyer! Default Avatar
    Joined
    03 Apr 2011
    Posted:
    583 messages
    Followed by:
    4 members
    Thanked:
    52 times
    Post Mon Mar 12, 2012 4:07 am
    IMO D

    goan81 Just gettin' started! Default Avatar
    Joined
    24 Jan 2011
    Posted:
    2 messages
    Post Mon Mar 12, 2012 11:24 pm
    d = distance of the train from the opening P when the man first notices the train
    r = speed of the train
    m = speed of man

    Equating the time required for the train and man to meet

    1) d/r = 3/m

    2) (d+8)/r = 5/m

    d/3r = (d+8)/5r

    solving the above equation gives d = 12

    substituting for d in 1)

    12/r = 3/m
    gives

    r = 4m

    (D)

    Best Conversation Starters
    1 varun289 42 topics
    2 JeneAleEngend 23 topics
    3 guerrero 21 topics
    4 sana.noor 20 topics
    5 tycleEmetly 20 topics
    See More Top Beat The GMAT Members...

    Most Active Experts
    1 image description Brent@GMATPrepNow

    GMAT Prep Now Teacher

    		 202 posts
    2 image description GMATGuruNY

    The Princeton Review Teacher

    		 140 posts
    3 image description Anju@Gurome

    Gurome

    		 113 posts
    4 image description Jim@StratusPrep

    Stratus Prep

    		 92 posts
    5 image description Jon@Admissionado

    Admissionado

    		 45 posts
    See More Top Beat The GMAT Experts