Two trains of equal length take 10 sec and 15 sec respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction ?
A. 16 sec
B. 15 sec
C. 12 sec
D. 10 sec
Answer: Option C
Solution(By Examveda Team)
$$\eqalign{ & {{\text{S}}_1} = \frac{{120}}{{10}}{\text{ m/sec}} \cr & \,\,\,\,\,\,\,\, = {\text{12 m/sec}} \cr & {{\text{S}}_2} = \frac{{120}}{{15}}{\text{ m/sec}} \cr & \,\,\,\,\,\,\,\, = 8{\text{ m/sec}} \cr} $$Time taken to cross each other :
$$\eqalign{ & {\text{ = }}\frac{{{l_1} + {l_2}}}{{{{\text{V}}_{{\text{rel}}{\text{.}}}}}} \cr & = \frac{{240}}{{20}} \cr & = 12\sec \cr} $$
Related Questions on Speed Time and Distance
A. 48 min.
B. 60 min.
C. 42 min.
D. 62 min.
E. 66 min.
A. 262.4 km
B. 260 km
C. 283.33 km
D. 275 km
E. None of these
A. 4 hours
B. 4 hours 30 min.
C. 4 hours 45 min.
D. 5 hours
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