The distance between two cities X and Y is 270 km. First train starts from X at 7:00 a.m. and travels towards Y at 40 km/hr. Second train starts from Y at 8:30 a.m. and travels towards X at 30 km/hr. At what time (in a.m.) will both the trains meet?
1). 11:15
2). 10:30
3). 11:30
4). 1:30
⇒ Total distance travelled by first train in 1 and half hour (from 7:00 am to 8:30 am) = speed × time = 40 × {1 + (1/2)} = 40 × (3/2) = 60 km
⇒ Total distance to be covered now = 270 – 60 = 210 km
⇒ Relative speed = 40 + 30 = 70 km/hr
⇒ Time taken = distance/speed = 210/70 = 3 hr
∴ They will meet at 11:30 am ie. (8:30 am + 3 hrs)