Two mixers and one T.V. cost Rs. 7000, while two T.V.s and a mixer cost Rs, 9800. The value of one T.V. is:

A. Rs. 2800   
B. Rs. 4200
C. Rs. 2100   
D. Rs. 8400
Answer:     B

Explanation:     

Let C.P. of a mixer be Rs. x and that of a T,V. be Rs. y.
Then, 2x + y = 7000 and 2y + x = 9800.
Multiplying 2nd equatien by 2 and subtracting first from it, we get
3y = 19600 - 7000 = 12600 or y = 4200 C.P. of a T.V. = Rs. 4200