Question

A train 150 m long, passes a pole in 15 s and
another train of the same length travelling in the opposite
direction in 12 s. The speed of the second train is
(a) 45 km/h (b) 48 km/h (c) 52 km/h (d) 54 km/h


(Why isn't the answer 45 kmph??????)​

Answer 1

Answer:

Let the speed of the second train be x m/s

Speed of first train =

150

= 10 m/sec

15

Relative speed of trains

= (x + 10) m/s

Total distance covered

= 150 + 150 = 300 metre

∴ Time taken =

300

x + 10

⇒

300

= 12

x + 10

⇒ 12x + 120 = 300

⇒ 12x = 300 – 120 = 180

⇒ x =

180

= 15 m/s

12

=

15 × 18

or 54 kmph.

5

Answer 2

Answer:

d. 54 km/h

Step-by-step explanation:

hope this was helpful