<|im_start|>system
You are a helpful assistant. You first think about the reasoning process in the mind and then provide the user with the answer. You should try to truely solve the question by yourself without cheating.  <|im_end|>
<|im_start|>user
 A 600 meter long train crosses a signal post in 40 seconds. How long will it take to cross a bridge of a certain length at the same speed if it takes 20 minutes to cross the bridge? Show your work in <think> </think> tags. And return the final answer in <answer> </answer> tags.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>
user
1240
A 600 meter long train crosses a signal post in 40 seconds. How long will it take to cross a bridge of a certain length at the same speed if it takes 20 minutes to cross the bridge?
test