Question

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

Answer 1

• B) m + 7

Explanation:

Given

• x = (m + 9)/2
• y = (2m + 15)/2
• z = (3m + 18)/2

To find

• Average of x, y and z

Solution

Average of x, y and z is:

• (x + y + z)/3

Substituting the values of x, y and z

• ((m + 9)/2 + (2m + 15)/2 + (3m + 18)/2)/3 =
• ((m + 9+ 2m + 15 + 3m + 18)/2)/3 =
• (6m + 42)/6 =
• m + 7

Correct option is B) m + 7

Answer 2

B) m + 7

Explanation:

We know that we have:

(m + 9)/2 = x

(2m + 15)/2 = y

(3m + 18)/2 = z

We need to find the average.

= (x + y + z)/3

= (m+9/2) + (2m+15/2) + (3m+18/2) / 3

= (m + 9) + (2m + 15) + (3m + 18) / 6

= (6m + 42) / 6

= (m + 7)

Best of Luck!