Question

the average of three numbers is 5 . if the sum of the first two numbers is 6 then the third number is ?

Answer 1

hope it helpss......!!

Answer 2

The third number is 9.

Given,

The average of three numbers = 5,

the sum of the first two numbers = 6.

To find,

The third number.

Solution,

It can be seen that the average of 3 numbers is given to be 5, and the sum of the first 2 numbers is 6.

Now, we know that the average of 3 numbers will be given as

$average=\frac{1st \hspace{4} no.+ 2nd \hspace{4}no. + 3rd \hspace{4} no.}{3} \hfill ...(1)$

Substituting the given values in the above equation (1),

$5=\frac{1st \hspace{4} no.+ 2nd \hspace{4}no. + 3rd \hspace{4} no.}{3}$

$\implies 1st \hspace{4} no.+ 2nd \hspace{4}no. + 3rd \hspace{4} no.= 5 \times 3$

$\implies 1st \hspace{4} no.+ 2nd \hspace{4}no. + 3rd \hspace{4} no.= 15$

Now, the sum of the first two numbers = 6.

Substituting it in the above equation, we get,

$6 + 3rd \hspace{4} no.= 15$

$\implies 3rd \hspace{4} no.= 15-6$

⇒ 3rd number = 9.

Therefore, the third number is 9.

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