Bunuel wrote:
Two trains continuously travel between Washington D.C. and Baltimore which are 120 miles apart. The trains start simultaneously, with train A starting in Washington DC and train B starting in Baltimore, and travel at 30 and 90 mph respectively. If the station turnaround times are negligible, what is the distance between the point where the trains meet for the first time and the point where they meet for the second time?
A. 0
B. 30 miles
C. 60 miles
D. 90 miles
E. 120 miles
Distance = 120 miles
A's speed : B's speed = 30:90 = 1:3
first meeting point -
A's distance = 1/4 x 120 = 30
B's distance = 3/4 x 120 = 90
So first meeting point is at 30 miles from Washington
At each meeting point, distance by A: distance by B will always be multiple of 1:3
When A=40 B = 120 (not meeting)
When A=50 B = 150 = -30 (not meeting : '-' implies change in direction)
When A =60 B = 180 = -60 (meeting)
So second meeting point is 60 miles from Washington.
Difference between meeting points is 60 -30 =30 miles