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

Dont give incorrect answer pls and solve it quickly i need its answer please......

​

Answer 1

Answer:

HI MATE !

In particular, we want mean of x, y, and z in terms of m.

So, we need two formulas:

(1) Arithmetic mean for x, y, and z, and

(2) we need x, y, z in terms of m.

(3) Then we can combine (1) and (2) to make (1) using only m, as required.

Lets find this by using definition of (1) Average and (2) what is given in question.

(1): A = (x + y + z )/3

(2):

x = (m + 9)/2,

y = (2m + 15)/2,

z = (3m + 18)/2

But (2) can also be written as

(2x) = m+9;

(2y) = 2m + 15;

(2z) = 3m + 18.

Now, lets multiply (1) by 2 and by 3. Gives:

(3): 2A * 3 = (2x) + (2y) + (2z)

And we have 2x, 2y, and 2z from (2) above. Lets combine (2) and (3)

We have:

2A * 3 = (2x) + (2y) + (2z)

2A * 3 = (m+9) + (2m + 15) + (3m + 18)

2A * 3 = 6m + 3*(3+5+6)

now lets divide both sides by 3 to simplify.

2A = 2m + (3+5+6)

But we want A (the average) not 2A, so lets simplify.

A = m + (14)/2

A = m + 7

Hope my answer helps you Dear.. ✌️

☺️

:-)

Answer 2

Answer:

hope it's helpful and Mark me as brainlist and follow me

Step-by-step explanation:

Well its straight forward. I think it must seem harder because of test anxiety.

Lets start with end goal and work our way back. In particular, we want mean of x, y, and z in terms of m.

So, we need two formulas:

(1) Arithmetic mean for x, y, and z, and

(2) we need x, y, z in terms of m.

(3) Then we can combine (1) and (2) to make (1) using only m, as required.

Lets find this by using definition of (1) Average and (2) what is given in question.

(1): A = (x + y + z )/3

(2):

x = (m + 9)/2,

y = (2m + 15)/2,

z = (3m + 18)/2

But (2) can also be written as

(2x) = m+9;

(2y) = 2m + 15;

(2z) = 3m + 18.

Now, lets multiply (1) by 2 and by 3. Gives:

(3): 2A * 3 = (2x) + (2y) + (2z)

And we have 2x, 2y, and 2z from (2) above. Lets combine (2) and (3)

We have:

2A * 3 = (2x) + (2y) + (2z)

2A * 3 = (m+9) + (2m + 15) + (3m + 18)

2A * 3 = 6m + 3*(3+5+6)

now lets divide both sides by 3 to simplify.

2A = 2m + (3+5+6)

But we want A (the average) not 2A, so lets simplify.

A = m + (14)/2

A = m + 7