Question

If x is the average of m and 9, y is the average of 2m and 15 and z is the average of 3 m and 18, what is the average of x, y and z in terms of m?

Answer 1

Answer:

(3m + 21) / 2

Step-by-step explanation:

x is the average of m and 9, hence, 2x = m + 9................eq(1)

y is the average of 2m and 15, hence, 2y = 2m + 15................eq(2)

z is the average of 3m and 18, hence, 2z = 3m + 18................eq(3)

Adding eq(1), eq(2) and eq(3)

2x + 2y + 2z = m + 9 + 2m + 15 + 3m + 18

or, 2(x + y + z) = 6m + 42

or, x + y + z = 3m + 21

or, (x + y + z)/2 = (3m + 21) / 2