The average (arithmetic mean) of four numbers is 5x + 6. If one of the numbers is 2x, what is the average of the other three numbers? Options:
A) x + 1
B) 3x + 3
C) 5x + 1
D) 5x + 4
E) 6x + 8
The sum of all four numbers is 4 * (5x + 6) = 20x + 24.   If one of the numbers is 2x, the sum of the other 3 numbers is 18x+24.   The average of the remaining three numbers is (18x+24)/3 = 6x+8.   The answer is 6x + 8.
<result>E</result>
The average (arithmetic mean) of four numbers is 5x + 6. If one of the numbers is 2x, what is the average of the other three numbers?