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A train 100 meter long meets a man going in opposite direction at 5 km/h and passes him in 7¹/₅ seconds. What is the speed of the train (in km/hr)?

145 km/h
260 km/h
355 km/hr
450 km/hr

Answer:- 1

Explanation:-

Solution:

\begin{aligned} Relative speed of man \&  train \\ = \frac{100 \times 5}{36} \times \frac{18}{5} \\ =  50km/hr \\ ∴ speed of train \\ =  50 - 5 \\ =  45 km/hr \end{aligned}

$\eqalign{ & {\text{Relative speed of man \& train}} \cr & {\text{ = }}\frac{{100 \times 5}}{{36}} \times \frac{{18}}{5} \cr & {\text{ = 50km/hr}} \cr & \therefore {\text{speed of train}} \cr & {\text{ = 50}} - {\text{5}} \cr & {\text{ = 45 km/hr}} \cr}$

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", "dateCreated": "7/24/2019 10:09:12 AM", "author": { "@type": "Person", "name": "Nitin Sir" } }, "suggestedAnswer": { "@type": "Answer", "text": "

Solution:

\begin{aligned} Relative speed of man \&  train \\ = \frac{100 \times 5}{36} \times \frac{18}{5} \\ =  50km/hr \\ ∴ speed of train \\ =  50 - 5 \\ =  45 km/hr \end{aligned}

$\eqalign{ & {\text{Relative speed of man \& train}} \cr & {\text{ = }}\frac{{100 \times 5}}{{36}} \times \frac{{18}}{5} \cr & {\text{ = 50km/hr}} \cr & \therefore {\text{speed of train}} \cr & {\text{ = 50}} - {\text{5}} \cr & {\text{ = 45 km/hr}} \cr}$ ", "dateCreated": "7/24/2019 10:09:12 AM" } }

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