A train leaves the station at 10:00 and travels due south at a speed of 60km/h. Another train has been heading due west at 45 km/h and reaches the same station at 11:00. At what time were the two closest together?
totally stuck on this one.
Let x be the distance between A and B in km
Let a and b be the distance travelled by A and B in km
Min x at t=?
x'=0 when t=0
domain of t
therefore the min distance between train A and train B is 750 km at 10:00
BUT>>> the back of the book's answer is: t=0.36 h
How do i get this and what did I do wrong?
the first train starts at the origin and moves away from the origin at 60 km/hr
the second train started 45 km away from the origin, and heads back toward the origin at 45 km/hr.
you see, after 1 hr, km from the origin. it made it back.