Janet is afraid of the dark, especially dark caves and tunnels.
Today Janet must catch the train into town. But there’s a problem. As soon as the train leaves the station, it goes into a tunnel.
Luckily, the tunnel isn’t too long – about 500 metres or so. But Janet still hates every second she’s in there.
While she’s waiting for the train, Janet has a few minutes to think about the tunnel, and she realises she should sit in the last carriage of the train.
Can you work out why she wants to sit at the back of the train? On the way home, which carriage should she sit in?
When the train leaves the station, how fast is it going? What about when it leaves the tunnel?
When the train leaves the station, it starts speeding up. By sitting at the back of the train, Janet gives the train more time to speed up before her seat enters the tunnel. And that means she spends less time in the tunnel than she would if she sat at the front of the train!
On the way home, the train will slow down as it enters the station. That means the back of the train will go very slowly through the tunnel. Janet should choose to sit in the front instead.
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