Question

Scholars caught, marked and released 80 fishes in a pound. Later 100 fishes were caught at random. 40 of them were marked. The number of fishes in the pond is

• A. 400
• B. 200
• C. 100
• D. 50

Answer 1

Answer: (B)

200

Let's take the total number of fishes in the pond be x.

When 80 fishes are marked, then the ratio of tagged fishes to total fishes is 80/x

When 100 fishes were caught out of which 40 were marked, then the ratio of tagged fishes to total fishes is 40/100

Taking the distribution of fishes in the pond to be uniform, the ratio of tagged fishes to the total fishes will be same in both the situations.

Hence, the equation can be shown as:

80/x = 40/100

This comes out to be 200

So, the correct answer is '200'.