Question 736354
Being very informal, you may have a proportion.  8 fish tagged to 40 fish caught is similar to 60 fish tagged to p fish in the lake.


We assume that the 60 tagged fish distributed themselves equally throughout the lake.  When this is achieved, the ratio of tagged fish to the whole population of fish in the lake is 60:p, using p as the count (unknown) of fish in the lake.  


{{{8/40=60/p}}}, and we would just solve for p.