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