SOLUTION: Hi a train 128 meters long travelled through a tunnel at an average speed of 18m per sec. The whole train took 2min 36sec to pass through the tunnel. A car entered the same tunne

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Question 1107038: Hi
a train 128 meters long travelled through a tunnel at an average speed of 18m per sec. The whole train took 2min 36sec to pass through the tunnel. A car entered the same tunnel 1min later than the train. Both the train and the car reached their destination which was 2km awayfrom the tunnel at the same time.
How long was the tunnel
what was the average speed of the car in meters per second.
thanks
Answer by ikleyn(52752)   (Show Source): You can put this solution on YOUR website!
.
1.  First find the length of the tunnel, x (in meters).


    The train covers the length of the tunnel plus its own length in 2 min 36 seconds = 120 + 36 = 156 seconds.

    Hence, for the speed you have this equation   = 156, which gives

        x = 156*18-128 = 2680 meters.


    The length of the tunnel is 2680 meters.



2.  Both the train and the car reached their destination at the same time:

        train's time = car's time
       
           =  + 60         (60 = 1 minute = 60 seconds;   r is the car' speed in meters per second)
                                                   

    It is your equation to find the car' speed.

    Left side of the equation is   = 260.  Hence, you have, step by step

        260 =  + 60,

        260 - 60 = ,

        200 =   ====>  r =  = 23.4 m/s


Answer.  The length of the tunnel is 2680 meters.  The speed of the car is 23.4 m/s = 84.24 km/hour.


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