Use some thinking to answer the following question. If the average (arithmetic mean) of the four numbers K, 2K + 3, 3K – 5 and 5K + 1 is 30, what is the value of K?
Options:
(A)  11
(B)  15 3/4
(C)  22
(D)  23
(E)  25 3/10
K + 2K +3 + 3K - 5 + 5K +1 = 11K -1
(11K -1)/4 = 30
11K = 30 * 4 +1 = 120 +1 = 121
K = 121 / 11 = 11. So the final answer is (A).