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Problems On Trains
Question 21 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
A 280 meter long train crosses a platform thrice its length in 50 seconds. What is the speed of the train in km/hr?
82.38 | |
60.48 | |
80.64 | |
64.86 |
Question 21 Explanation:
\begin{align} & {\text{Length of train}} \cr & {\text{ = 280 m }} \cr & {\text{Length of platform}} \cr & {\text{ = (3}} \times {\text{280) m = 840m}} \cr & {\text{Speed of train}} \cr & {\text{ = }}\left( {\frac{{280 + 840}}{{50}}} \right)m/\sec \cr & \frac{{1120}}{{50}}m/\sec \cr & = \left( {\frac{{1120}}{{50}} \times \frac{{18}}{5}} \right)km/hr \cr & = 80.64\, km/hr \cr\end{align}
Question 22 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
A train passes two bridges of length 500 m and 250 m in 100 seconds and 60 seconds respectively. The length of the train is?
250 m | |
152 m | |
120 m | |
125 m |
Question 22 Explanation:
\begin{align} & {\text{Let the length of train }}x{\text{ m }} \cr & {\text{Speed of train }} \cr & {\text{ = }}\frac{{\left( {{\text{Length of train + length of bridge }}} \right)}}{{{\text{Time taken in crossing}}}}{\text{ }} \cr & {\text{According to information we get}} \cr & \Rightarrow \frac{{x + 500}}{{100}} = \frac{{x + 250}}{{60}} \cr & \Rightarrow 60\left( {x + 500} \right) = 100\left( {x + 250} \right) \cr & \Rightarrow 3\left( {x + 500} \right) = 5\left( {x + 250} \right) \cr & \Rightarrow 5x + 1250 = 3x + 1500 \cr & \Rightarrow 5x - 3x = 1500 - 1250 \cr & \Rightarrow 2x = 250 \cr & \Rightarrow x = \frac{{250}}{2} = 125\, {\text{m}} \cr\end{align}
Question 23 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
A train of length 150 meters takes 40.5 seconds to cross a tunnel of length 300 meters. What is the speed of the train in km/hr?
13.33 | |
66.67 | |
40 | |
26.67 |
Question 23 Explanation:
\begin{align} & {\text{Speed = }}\left( {\frac{{150 + 300}}{{40.5}}} \right)m/\sec \cr & = \left( {\frac{{450}}{{40.5}} \times \frac{{18}}{5}} \right)km/hr \cr & = 40km/hr. \cr\end{align}
Question 24 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
Two trains are running at 40 km/hr and 20 km/hr respectively in the same direction. Fast train completely passes a man sitting in the slower train in 5 seconds. What is the length of the fast train?
27 7/9 m | |
23 m | |
29 m | |
23 2/9 m |
Question 24 Explanation:
\begin{align} & {\text{Relative}}\, {\text{speed}} = \left( {40 - 20} \right)\, {\text{km/hr}} \cr & = \left( {20 \times \frac{5}{{18}}} \right)\, {\text{m/sec}} \cr & = \left( {\frac{{50}}{9}} \right)\, {\text{m/sec}} \cr & \therefore {\text{Length}}\, {\text{of}}\, {\text{faster}}\, {\text{train}} \cr & = \left( {\frac{{50}}{9} \times 5} \right)\, m \cr & = \frac{{250}}{9}\, m \cr & = 27\frac{7}{9}\, m \cr\end{align}
Question 25 [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER] |
A train running at a speed of 90 km/hr crosses a platform double its length in 36 seconds. What is the length of the platform in meters?
300 | |
200 | |
Can not be determined | |
None of these |
Question 25 Explanation:
\begin{align} & {\text{Let the length of the train be x metres}}{\text{.}} \cr & {\text{Then, length of the platform = (2}}x{\text{) metres}}{\text{.}} \cr & {\text{Speed of the train}} \cr & {\text{ = }}\left( {90 \times \frac{5}{{18}}} \right)m/\sec \cr & = 25m/sec \cr & \therefore \frac{{x + 2x}}{{25}} = 36 \cr & \Rightarrow 3x = 900 \cr & \Rightarrow x = 300 \cr & {\text{Hence, length of platform}} \cr & {\text{ = }}2x = \left( {2 \times 300} \right){\text{m}} = 600{\text{m}} \cr\end{align}
There are 25 questions to complete.