[CV085] Train Speed

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Train Speed
Game	Professor Layton and the Curious Village
Number	085
Type	Write Answer
Location	Outside the Sewer
Solved by	Luke
Picarats	50
Mandatory	No
Reward	Furniture (Fossil)
In other languages
Deutsch	Zugtempo
Español	Tren desbocado
Français	Le pont et le train
Italiano	Il treno sul ponte
한국의	열차의 속도 (Train Speed)

Train Speed is a puzzle in the European version of Professor Layton and the Curious Village. For the puzzle in the American version of the game, go here.

Puzzle

A train with a length of 100m takes 30 seconds to travel over a 400m bridge.

Assuming that the train's speed is constant, how many kilometres per hour is it travelling at?

Hints

• →
• Hint 1
• Hint 2
• Hint 3

Click a Tab to reveal the Hint.

You're probably thinking that this is a really bothersome calculation problem.

Actually, there's a really easy way to work it out. Just make sure you get all the numbers right before you start.

A 100m train travelling over a 400m bridge in 30 seconds. So you have to divide 400 by 30, right?

Well, the train starts travelling over the bridge the moment the front of the train is on the bridge, and it finishes once the end of the train has moved off the bridge.

How far has the train travelled in this time?

Can you see that the train must travel 500m in order to travel completely over the bridge?

If so, the rest is easy. 500m is 0.5km. 30 seconds is 0.5 minutes.

Solution

Incorrect

Too bad!

Correct

That's right!

The answer is just a matter of arithmetic, but you need to be using the right figures. If the time between the front of the train travelling onto the bridge and the back of the train travelling off the bridge is 30 seconds, then the distance travelled in that time is 500m. This means the train travels 1km per minute, which is 60 km per hour.