If the average (arithmetic mean) of a and b is 100, and the average of b and c is 160, what is the value of a − c?  Choose one
A) −120	B) −100	C) 100	D) 135	E) It cannot be determined from the information given
Question: a - c = ?   (a + b)/ 2 =100 ===&gt; a + b = 200   (b + c)/2 = 160 ===&gt; b + c = 320   (a + b) - (b + c) = 200 - 320 ===&gt; a + b - b - c = - 120 ===&gt; a - c = - 120   −120nswer: −120
<result>A</result>
If the average (arithmetic mean) of a and b is 100, and the average of b and c is 160, what is the value of a − c?