Data Sufficiency (DS) | Re: What is the average of x, y, and z?

Target question: What is the average of x, y, and z?

NOTE:the average of x, y and z = (x + y + z)/3

Statement 1: 2x + y + 4z = 23
This statement doesn't FEEL sufficient, so I'll TEST some values.
There are several values of x, y and z that satisfy statement 1. Here are two:
Case a: x = 0, y = 23 and z = 0. In this case,the average of x, y and z = (0 + 23 + 0)/3 = 23/3
Case b: x = 11, y = 1 and z = 0. In this
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