<|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
 Brian has the same percentage of white stones and black stones in his collection of 100 stones as he does of grey stones and green stones in a separate collection. He has 40 grey stones and a certain number of green stones. If he has more white stones than black ones and has 60 white stones, how many green stones does he have? 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
27
Brian has the same percentage of white stones and black stones in his collection of 100 stones as he does of grey stones and green stones in a separate collection. He has 40 grey stones and a certain number of green stones. If he has more white stones than black ones and has 60 white stones, how many green stones does he have?
test