They catch a sample of 87 trout and tag them. They then release these trout.
The next day they catch another sample of 70 trout and find 14 of these trout had been tagged the previous day.Estimate the total number of trout in the lake.
Marked fish in the sample : All fish in the sample.
Marked fish in the lake : All fish in the lake.
We assume that these ratios are approximately equal.
Is that enough to get you started?
I would have just assumed you use the formula for biology (fish in first sample which are marked and released x fish caught in second sample) / fish marked in second sample. So 87*70/14?
the estimated number of is 435