Question

a train 26 m long is running at the speed of 45 km per hour what time will it take to cross a pole 140 metre long Bridge

Answer 1

Hope u like my process.
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$= > 45 \: \: km \: \: {hr}^{ - 1} = \blue{\frac{45 \times 1000}{3600} \: m {s}^{ - 1} } \\ \\ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: = \blue{12.5 \: m {s}^{ - 1} }$
=> Total distance train have to travel is

= 2× it's length + 140

= (2×26) + 140 = 52 + 140 = 192 m

Thus time taken to cross a pole
$= > time \: \: \: taken= \frac{d}{v} = \frac{192}{12.5} \\ \\ = 15.36 \: \: sec$

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