CareerCup

Solution for this case is very simple. Just ask the first person to add a random value to his salary and pass it on to the next person. The other person will add his salary value to it and pass it on to the other. Finally, the total sum is passed on to first person. He subtracts his value to get the total sum. Finding the average is then trivial.

a, b, c - salaries

For each cases divide salaries into random pieces
a = a1 + a2
b = b1 + b2
c = c1 + c2

first A will tell a1 to B , now b will add b1 to a1 and send [a1+b1] to C
Now C will add c1 to this . Now C have s1=[a1+b1+c1].

Now C will send c2 to B and B will add b2 to this and send [c2+b2] to A, now A will add a2 tho this. So A have s2=[a2+b2+c2]

Now Finally set average by [s1+s2]/3

a, b, c - salaries

For each cases divide salaries into random pieces
a = a1 + a2
b = b1 + b2
c = c1 + c2

a and c tells a1 and c1 to b: a1 + b1 + c1 = s1
a and b tells a2 and b2 to c: a2 + b2 + c2 = s2
(s1 + s2)/3 - average

Good solution!

May be we can do the same by using friendly function in C++

The random number answer sounds great.

Let A, B and C disclose their salaries to D, and D do the calculation and then tell them the average.

Each salary divided by 3.
A gives a1 to B, a2 to C and left a3
B gives b1 to A, b2 to C and left b3
C gives c1 to A, c2 to B and left c3
A+B+C - their sum
whole salaries have not been disclosed

:-)

there is no mention that a forth person's help should not be used.

A picks 2 random numbers, a1 and a2, such that average(a1, a2)=salary(A). B and C do the same.

A gives a1 to B, who calculates B'=average(a1, b2)
B gives b1 to C, who calculates C'=average(b1, c2)
C gives c1 to A, who calculates A'=average(c1, a2)

Now the A', B' and C' can be revealed and final average calculated.

salary A + random A ( A gives this to B )

salary A + random A
salary B + random B ( B gives this to C )

salary A + random A
salary B + random B
salary C + random C ( C gives this to A )

salary A+
salary B + random B
salary C + random C ( A removes random A & gives the total to B )

salary A+
salary B+
salary C+ random C ( B removes random B & gives the total to C )

salary A+
salary B+
salary C+ ( C removes random C & gives the total to A )

now A has the total of their salaries from which Average can be calculated..

c fixes 2 arbitary nos x and y....he tell x to a and y to b
a adds x to his salary and passes the sum to b..
b adds y to his salary and adds a's pseudo salary to it and passes it to c..
c subtracts x+y from the sum and adds his salary to it and divides it by 3...

now the avg is declared!!!!

Adding to above comments.

A->6$ , B->5$ c->10$ ( c fixed 2$ fake salary for a and 3$ for b)

1.A- 6+2...passes to b..
2.B- 5+3+(A pseudo salary which is 8?)=16..pass to c.
3.c- 16-(2+3)=11+(his real salary)/3