Tuesday
March 28, 2017

Post a New Question

Posted by on .

Trains A and B are traveling in the same direction on parallel tracks. Train a is traveling at 100 mph and train B is traveling 120 mph. Train a passes a station at 7:20 P.M. If train B passes the same station at 7:35 P., at what time will train B catch up to train A?

  • math/algebra - ,

    By 7:35, train A would have gone 15min. past the station. The distance travelled would have been 100 mph*15/60 hours = 25 miles.
    Train B catches up at the rate of 120-100 mph=20 mph. How long would it take to catch up?

  • math/algebra - ,

    7:35 PM - 7:20 PM = 15 min = 0.25 h,

    When train B catches up with A, their
    distance traveled will be equal. But A
    traveled that distance in 15 min(0.25h)
    less. Therefore:

    d1 = d2,
    100t = 120(t - 0.25),
    100t = 120t - 30,
    100t - 120t = -30,
    -20t = -30,
    t = 1.5 h = train A time traveled.
    (t - 0.25) = 1.5 - 0.25 = 1.25 h =
    1:15 = Time needed for B to catchup,

    B caughtup at: 7:35 PM + 1:15 = 8:50PM.

Answer This Question

First Name:
School Subject:
Answer:

Related Questions

More Related Questions

Post a New Question