| Two trains 140 m and 160 m long are running at the speeds of 60 km/h and 40 km/h, respectively in opposite directions on parallel tracks. The time (in seconds) which they take to cross each other, is |
A) 10
B) 10.8
C) 9
D) 9.6
Correct Answer: B
Solution :
| Total length of trains \[=140+160=300\,m\] |
| Relative speed \[=60+40=100\text{ }km/h\] |
| \[=100\times \frac{5}{18}\,\,m/s\,\,\,=\frac{250}{9}\,\,m/s\] |
| \[\therefore \] Time taken to cross each other |
| \[=\,\,\frac{300}{\frac{250}{9}}\,\,=\,\,\frac{300\times 9}{250}=10.8\,s\] |
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