Question

Here are two sets of numbers, a and b. Set a :200,104,100,160. Set b: 270,400,483,300, x. Mean of set a: mean of set b= 3:8. Work out the value of x

Answer 1

Given:

The given sets are:

Set a : 200, 104, 100, 160.

Set b: 270, 400, 483, 300, x.

Mean of set a: mean of set b= 3:8

To find:

The value of x.

Solution:

Formula for mean:

$Mean=\dfrac{\text{Sum of observations}}{\text{Number of observation}}$

The mean of set of a is:

$Mean=\dfrac{200+104+100+160}{4}$

$Mean=\dfrac{564}{4}$

$Mean=141$

The mean of set of b is:

$Mean=\dfrac{270+400+483+300+x}{5}$

$Mean=\dfrac{1453+x}{5}$

$Mean=\dfrac{1453+x}{5}$

It is given that,

Mean of set a: mean of set b= 3:8

$\dfrac{141}{\dfrac{1453+x}{5}}=\dfrac{3}{8}$

$\dfrac{705}{1453+x}=\dfrac{3}{8}$

$8\times 705=3\times (1453+x)$

$5640=4359 +3x$

Isolate the variable x.

$5640-4359 =3x$

$1281 =3x$

Divide both sides by 3.

$\dfrac{1281}{3} =x$

$427 =x$

Therefore, the value of x is 427.