Average salary without disclosing salary

Three coworkers would like to know their average salary. how can they do it, without disclosing their own salaries?

Solution:

Let's say the three co-workers are A, B, and C and their individual salaries are Sa, Sb, and Sc respectively. For knowing the average of their salaries without disclosing their own salaries to each other, they follow these steps:-

* A adds a random amount, say Ra to his own salary and gives that to B (B won't be able to know A's salary as he has added a random amount known to him only). In this case, B will receive the figure (Sa + Ra) from A.
* B does the same and gives the final amount to C (without showing that to A). Now C will get the figure (Sa + Ra + Sb + Rb).
* C does the same and gives the final figure to A (without showing it to B). Now, A will receive the figure (Sa + Ra + Sb + Rb + Sc + Rc).
* Now A subtracts his random amount and gives the final figure to B (without showing that to C). B will now receive the figure (Sa + Sb + Rb + Sc + Rc).
* B subtracts his random amount and gives the final figure to C (without showing it to A). C will receive the figure (Sa + Sb + Sc + Rc).
* C subtracts his random amount and then the figure becomes (Sa + Sb + Sc). It's shown to everyone and by they get to know the average simply by dividing this figure by 3.

Very good puzzle