The average monthly income of A and B is Rs.7,000. The average monthly income of B and C is Rs. 7,750 and the average monthly income of C and A is Rs.6,750. What is the monthly income of B?

Rs. 8,000

Sum of income of A and B = 7000 X 2 = 14000

Sum of income of B and C = 7750 x 2 = 15500

Sum of income of A and C = 6750 X 2 = 13500

By solving these equations

⇒ Income of B = Rs 8000