The averageincome of M and N is Rs. 5050. The average monthly income of N and O is Rs. 6250 and the average monthly income of M and Ois Rs. 5200. The income of M is?  Choose the correct answer:
A) rs . 2000 B) rs . 3000 C) rs . 4000 D) rs . 4500 E) rs . 5000

Rationale: let p , q and r represent their respective monthly incomes . then , we have : p + q = ( 5050 x 2 ) = 10100 . . . . ( i ) q + r = ( 6250 x 2 ) = 12500 . . . . ( ii ) m + o = ( 5200 x 2 ) = 10400 . . . . ( iii ) adding ( i ) , ( ii ) and ( iii ) , we get : 2 ( m + n + o ) = 33000 or m + n + o = 16500 . . . . ( iv ) subtracting ( ii ) from ( iv ) , we get m = 4000 . m ' s monthly income = rs . 4000 c
Answer: C