The ratio between the speed of two trains is 3 : 4. If the second train covers 2 km in 50 seconds, the speed of first train is.

30 m/sec 30 km/hr 40 m/sec 40 km/hr

30 m/sec

Speed = \(\frac{Distance}{Time}\) Speed of 2nd train =  \(\frac{2000}{50}\) m/sec = 40 m/sec    .....(i) Ratio of speed = 1st : 2nd = 3 : 4 4R = 40 m/sec              [from (i)] 1R = 10 m/sec Speed of 1st train = 3R =3 × 10 = 30 m/sec