Answer:
☁︎Question and Answer
If x is the average (arithmetic mean) of m and 9, y is the average of 2m and 15, and z is the average of 3m and 18, what is the average of x, y, and z in terms of m?
A) m+6
B) m+7
C) 2m+14
D) 3m+21
Step-by-step explanation:
ANSWER EXPLANATION:
Since the average (arithmetic mean) of two numbers is equal to the sum of the two numbers divided by 2, the
equations x= m+9/2,
y=2m+15/2, z=3m+18/2
are true.
The average of x, y, and z is given by
x+y+z/3.
Substituting the expressions in m for each variable (x, y, z) gives
[m+9/2+2m+15/2+3m+18/2]/3
This fraction can be simplified to m+7.
The final answer is B.
