A bag contains 16 congruent blocks, 4 of which are blue and 12 of which are red. Two blocks are randomly pulled from the bag at the same time. What is the probability that both blocks are blue? Express your answer as a common fraction.
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
A bag contains 16 congruent blocks, 4 of which are blue and 12 of which are red. Two blocks are randomly pulled from the bag at the same time. What is the probability that both blocks are blue? Express your answer as a common fraction.
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
\frac{1}{20}
A bag contains 16 congruent blocks, 4 of which are blue and 12 of which are red. Two blocks are randomly pulled from the bag at the same time. What is the probability that both blocks are blue? Express your answer as a common fraction.
train