The average (arithmetic mean) of four numbers is 4x + 1. If one of the numbers is x, what is the average of the other three numbers?	Choose the correct choice from the following options.
A) x + 1  B) 3x + 3  C) 5x + 4/3  D) 5x + 4  E) 15x + 12
If the average of four numbers is 4x + 1, then the sum of all four numbers if 4 * (4x + 1) = 16x + 12. If one of the numbers is x, then the average of the remaining three numbers would be: (16x + 4 - x)/3 = (15x + 4)/3 = 5x + 4/3.   Answer is 5x + 4/3.
<result>C</result>
The average (arithmetic mean) of four numbers is 4x + 1. If one of the numbers is x, what is the average of the other three numbers?