Question 988797
A biologist wants to estimate the number of fish living in a lake
 she caught 114 fish tagged each one and then released them back into the lake
 after a few days she got 260 fish and found that 21 of them were tagged use a proportion to estimate the number of fish living in this lake 
:
let x = estimated no. of fish in the lake
:
{{{x/114}}} = {{{260/21}}}
cross multiply
21x = 114 * 260
21x = 29640
x = 29640/21
x ~ 1400 fish in the lake