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 s… — Answer & Discussion

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?

A10:00
B11:00
C11:30
D12:30

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Discussion 1

CCommunity10 Jun 2019

⇒ 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)