Question

practice problem solve suppose you are helping scientists conduct a study of a population of clear lake hitch, which is a fish species that lives in californian lakes. the scientists initially capture 80 hitch from a lake and tag all of them. after 30 days, they capture 100 hitch and count 20 tags. use the space below to calculate the estimated number of hitch in the lake. show your work.

Explanation:

Step1: Set up proportion

Let $N$ be the total number of fish in the lake. The proportion is $\frac{\text{Number of tagged fish initially}}{\text{Total population}}=\frac{\text{Number of tagged fish in second - catch}}{\text{Size of second - catch}}$, so $\frac{80}{N}=\frac{20}{100}$.

Step2: Cross - multiply

Cross - multiplying gives $20N = 80\times100$.

Step3: Solve for $N$

$N=\frac{80\times100}{20}$.
$N = 400$.

Answer:

400