Answer:
The value is 
Step-by-step explanation:
From the question we are told that
The number of cans is n = 4
The number of can that are empty is N = 3
The number of can filled with water is k = 1
The number number of sets of cans is w = 5
Generally probability of detecting the correct can is mathematically represented as

=> 
=> 
Generally probability of not detecting the correct can is mathematically represented as



Generally the number of cans expected of the farmer to correctly identify by chance is mathematically represented as

=> 
=> 