K + 2K +3 + 3K - 5 + 5K +1 = 11K -1
(11K -1)/4 = 85
11K = 85 * 4 +1 = 340 +1 = 341
K = 253 / 11 = 31.
If the average (arithmetic mean) of the four numbers K, 2K + 3, 3K – 5 and 5K + 1 is 85, what is the value of K?
   11
   15 3/4
   31
   23
   25 3/10