If 20m − n = p, then which of the following represents the average (arithmetic mean) of m, n, and p, in terms of m?
Options
A) 2m −1 B) 4m C) 6m D) 7m E) 6m/5
20m - n = p   Add n to both sides:   20m = n + p   Add m to both sides:   21m = n + p + m   Now, divide both sides by 3   7m = (n + p + m)/3 = the average of n, p, and m   7m
<result>D</result>
If 20m − n = p, then which of the following represents the average (arithmetic mean) of m, n, and p, in terms of m?