<|im_start|>system
You are a helpful assistant. You first thinks about the reasoning process in the mind and then provides the user with the answer.<|im_end|>
<|im_start|>user
Using the numbers [11, 21, 31, 40], craft a Countdown equation that equals 152. Utilize basic arithmetic operations like +, -, *, and /. You must use each number only once. Show your working in <think> </think> tags, and present your solution in <answer> </answer> tags, for example <answer> (21 - 11) / (40 - 31) = 2 </answer>.<|im_end|>
<|im_start|>assistant
Let me solve this step by step.
<think>