Subscribe TechModgy to learn about new technologies!

Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 5 seconds. What is the length of the fast train ?

A. 2779

B. 2879

C. 2979

D. 3079

Please do not use chat terms. Example: avoid using "grt" instead of "great".