Two goods train each 500 m long, are running in opposite directions on parallel tracks. Their speeds are 45 km/hr and 30 km/hr respectively. Find the time taken by the slower train to pass the driver of the faster one.

A. 12 sec

B. 24 sec

C. 48 sec

D. 60 sec

Correct Answer : B.

R e l a t i v e s p e e d = (45 + 30) k m / h r = (75 x \frac{5}{18}) m / s e c = (\frac{125}{6}) m / s e c . W e h a v e t o f i n d t h e t i m e t a k e n b y t h e s l o w e r t r a i n t o p a s s t h e D R I V E R o f t h e f a s t e r t r a i n a n d n o t t h e c o m p l e t e t r a i n . S o, d i s \tan c e c o v e r e d = L e n g t h o f t h e s l o w e r t r a i n . T h e r e f o r e, D i s \tan c e c o v e r e d = 500 m . T h e r e f o r e R e q u i r e d t i m e = (500 x \frac{6}{125}) = 24 s e c .

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