Knowing that dogs live 4 times the age of hamsters, dogs live 4 * 2.5 = <<4*2.5=10>>10 years.

If Ruth takes care of the fish, it can live 10 + 2 = <<10+2=12>>12 years.

# Answer

12
<|im_start|>system
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<|im_start|>user
To let Ruth know how long her fish will live, her father tells her that well-cared fish can live 2 years longer than dogs live. On average, dogs live 4 times as long as hamsters live. And hamsters live an average of 2.5 years. How long can a fish live?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
12
To let Ruth know how long her fish will live, her father tells her that well-cared fish can live 2 years longer than dogs live. On average, dogs live 4 times as long as hamsters live. And hamsters live an average of 2.5 years. How long can a fish live?
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