<PRE><B>Question 708759</B>
A train takes 3 seconds to enter a tunnel which is 1 km long.
 If it is traveling at 120 km per hour, how long will it take to pass completely through the tunnel?
:
Find the speed in meters/sec when traveling at 120 kmh
{{{(120*1000)/3600}}} = 33.33 meters/sec
:
Find the length of the train which takes 3 sec to enter the tunnel
3 * 33.333 = 100 meters
:
For the train to completely clear the tunnels it will have to travel 1100 meters (1km + 100m)
{{{1100/33.333}}} = 30 seconds to completely pass trough the tunnel </PRE>