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 ?
Select the correct option:
A) 650 meter
B) 555 meter
C) 500 meter
D) 458 meter
E) None of these
Explanation:   Let length of tunnel is x meter   Distance = 800+x meter   Time = 1 minute = 60 seconds   Speed = 78 km/hr = 78*5/18 m/s = 65/3 m/s   Distance = Speed*Time   =&gt;800+x=65/3∗60   =&gt;800+x=20∗65=1300   =&gt;x=1300−800=500   So the length of the tunnel is 500 meters.   Option 500 meter
<result>C</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 ?