The second dog eats 26 pounds a week because 13 x 2 = <<13*2=26>>26

In total they eat 45 pounds because 3 x 15 = <<3*15=45>>45

The third dog eats 6 pounds a week because 45 - 13 - 26 = <<45-13-26=6>>6

# Answer

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<|im_start|>system
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<|im_start|>user
Arthur has 3 dogs. They eat an average of 15 pounds of food a week. One dog eats 13 pounds a week. The second eats double this. How much does the third dog eat a week?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
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user
6
Arthur has 3 dogs. They eat an average of 15 pounds of food a week. One dog eats 13 pounds a week. The second eats double this. How much does the third dog eat a week?
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