Here is my interpretation of this question.
Take aside the portion saying absolute values, we know basic average is simply adding all of the numbers and dividing by the number of numbers. Say R is -4, S is 1 and T is 2. We know the average would be (-4 + 1 + 2)/3.
The question itself is a very tricky/deceptive in the wording. It says the number line has the points R, S, and T with the absolute values of r, s, and t. While R, S and T might have absolute values of r, s and t, the question ultimately asks what the average of points R, S and T are, not r, s and t. The key might be in the use of the word "coordinate" which factors in positive/negative values, instead of the absolute value of r, s and t.
It wants the average to EQUAL the coordinates of R, S, and T. So all we need is an equation that equals the average of (-4 + 1 +2)/3. E (s + t - r)/3 is the only option that equals that.
Ultimately r, s, and t are absolute values, so the the average equation would have to incorporate a negative for r. So (|s| + |t| - (|r|))/3
Bunuel wrote:
mrai87 wrote:
The number line shown contains three points R, S, and T, whose coordinates have absolute values r, s, and t, respectively. Which of the following equals the average (arithmetic mean) of the coordinates of the points R, S, and T ?
A. s
B. s + t - r
C. (r - s - t)/3
D. (r + s + t)/3
E. (s + t - r)/3
Hi, I would also like to clarify this solution. If r is the absolute value of R and R is -R then why is the co-ordinate -r? If it is an absolute value it cannot be a negative number. Please explain?
Say R = -3, S = 1 and T = 2. In this case r = |-3| = 3, s = 1, and t = 2. The average of the coordinates of the points R, S, and T would be (2 + 1 + (-3))/3 so, (s + t - r)/3.