Use some thinking to answer the following question. The average of 13 numbers is 60. Average of the first 6 of them is 57 and that of the last 8 is 61. Find the 8th number?
Options:
(A) 46
(B) 48
(C) 50
(D) 52
(E) 54
Sum of all the 13 numbers = 13 * 60 = 780
Sum of the first 6 of them = 6 * 57 = 342
Sum of the last 8 of them = 8 * 61 = 488
So, the 8th number = 342 + 488 - 780 = 50. So the final answer is (C).