A train , 800 meter long is running with a speed of 78 km/hr. It crosses a tunnel in 1 minute. What is the length of the tunnel (in meters)? Choose the correct option
A) 440 m	B) 500 m	C) 260 m	D) 430 m	E) 450 m
Explanation:   Distance = 800+x meter where x is the length of the tunnel   Time = 1 minute = 60 seconds   Speed = 78 km/hr = 78×10/36 m/s = 130/6 = 65/3 m/s   Distance/time = speed   (800+x)/60 = 65/3   =&gt; 800+x = 20×65 = 1300   =&gt; x = 1300 - 800= 
<gadget id="calculator">1300 - 800</gadget>
<output>500</output>
500 meter   Answer: Option 500 m
<result>B</result>
A train , 800 meter long is running with a speed of 78 km/hr. It crosses a tunnel in 1 minute. What is the length of the tunnel (in meters)?