I agree that you can't get the exact answer, but what would Brian's equation give you as an estimate?

Question: Two of Brian's colleagues have different estimates for the salmon population next year. Zelda estimates that the salmon population will be 5000, while Zeke estimates that the salmon population will be 2000. What is Brian's bear population estimate for Zelda? What about Zeke? Which approximation is more likely to be accurate? Show work and/or explain your reasoning.