The average (arithmetic mean) of four numbers is 4x + 6. If one of the numbers is x, what is the average of the other three numbers?	Choose the correct answer.
A) x + 1	B) 3x + 3	C) 5x + 8	D) 5x + 4	E) 15x + 12
The sum of all four numbers is 4 * (4x + 6) = 16x + 24.   If one of the numbers is x, the sum of the other 3 numbers is 15x+24.   The average of the remaining three numbers is (15x+24)/3 = 5x+8.   The answer is 5x + 8.
<result>C</result>
The average (arithmetic mean) of four numbers is 4x + 6. If one of the numbers is x, what is the average of the other three numbers?