Let B be the cost of the blue socks

4*3 +6*Y =42

12 + 6*Y=42

6*Y =30

Y = <<5=5>>5

# Answer

5
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Luis needed to buy some socks. He bought 4 pairs of red socks and 6 pairs of blue ones. In total, he spent $42. If the red socks cost $3 each, how much did he pay for each blue pair?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
5
Luis needed to buy some socks. He bought 4 pairs of red socks and 6 pairs of blue ones. In total, he spent $42. If the red socks cost $3 each, how much did he pay for each blue pair?
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