Tunnel vision

What I know

-The train is 1000 meters travels through the 3000 meters tunnel

- 30 seconds pass from the last car completely entered the tunnel

? Determine the speed of the train in kilometers/per hour?

When the train enters the tunnel: 3000- 1000= 2000

So there is 2000 meters left to travel in the tunnel. Since the engine need to travel 2000 meters in 30 seconds, I will calculate the speed of the train by dividing the distance traveled by the time required to travel the distance

2000 divided by 30= 66.7 

66.7 is the speed of the train in 1 second

66.7 multiplied by 60 (because there are 60 seconds in a minute)= 4002 is in 1 minute

4002 multiplied by 60 (because there are 60 minutes in 1 hour)= 240,120 in 1 hour

Now I need to find the distance traveled in 1 hour

240,120 divided by 1000= 240.120 km which is how much the train travels per hour

Answer is the train traveled 240. 120 km per hour

OR

3000-1000=2000 when the train enters the tunnel

The engine has to travel 2000 m in 30 seconds

2000 divided by 30= 200/30 m/s that is the speed of the train

Now I am going to convert minutes/ seconds to kilometer/ hours

200 m/3 s multiplied by 1 km/1000 km 

200 km/ 3000 km= 1 km/ 15 s

1 km/15 multiplied by 60 s/1 min multiplied by 60 min/1 hour= 3600 km/ 15 hour

240 km/ 1 hour

Answer : 240 km / 1 hour the train traveled

So either way the answer will be 240 km/ 1 hour the trains speed