Question

Help to resolve the question? ​

Answer 1

hope it helps

have a great day

Answer 2

Topic :-

Arithmetic Mean

Given :-

A group of four numbers have average of 15. Three of the numbers are 18, 11 and 25.

To Find :-

The fourth number.

Solution :-

Let fourth number be 'x'.

$\boxed{\sf{Mean = \dfrac{Sum\:\:of\:\:terms}{Number\:\:of\:\:terms}}}$

It is given that,

• Mean = 15

• There are four numbers.

• Three given numbers are 18, 11 and 25.

Using the formula,

$15=\dfrac{18+11+25+x}{4}$

$15=\dfrac{54+x}{4}$

Now, cross multiply,

15 × 4 = 54 + x

60 = 54 + x

x = 60 - 54

x = 6

So, fourth number is 6.

Answer :-

So, fourth number is 6, which is option A.