Question

some researchers wanted to know how many salmon were in a local river. the researchers marked 640 salmon with tags. later, they captured 450 salmon and found that 16 of them had tags. to the nearest whole number, what is the best estimate for the salmon population?

Explanation:

Step1: Set up proportion

Let $N$ = total salmon population. The ratio of tagged salmon in the sample equals the ratio of tagged salmon in the whole population:
$$\frac{16}{450} = \frac{640}{N}$$

Step2: Solve for $N$

Cross-multiply to isolate $N$:
$$N = \frac{640 \times 450}{16}$$

Step3: Calculate the value

First compute $640 \div 16 = 40$, then multiply by 450:
$$N = 40 \times 450 = 18000$$

Answer:

18000