Question 325316
Trains A and B are traveling in the same direction on parallel tracks. 
Train A  60 miles per hour 
train B  70 miles per hour. 
Train A passes a station at 5:15 P.M. 
train B passes the same station at 5:45 P.M., 
..
train A speed = 60 mph
between 5.15 to 5.45 (1/2 hour)train A has traveled 30 miles
..
let train B catch up with train A after x miles.
time taken by train B = x/70 hours
..
Train A in the same time has traveled x-30 miles
speed = 60 mph
time taken = x-30/60
..
x-30/60 = x/70
70(x-30)=60x
70x-2100=60x
70x-60x= 2100
10x= 2100
x= 210 miles...
to travel 210 miles Train B will take 210/70= 3 hours.
it crossed the station at 5.45 pm
So it will catch up with train A at 8.45 pm

..