Question

The mean of the three numbers is 21. If two numbers are 16 and 22, then the third number is​

Answer 1

Answer:

sum of three numbers = 21×3=63

third number= 63-16-22= 25

Answer 2

Given

Mean of three numbers is 21

two numbers are 16 & 22.

To Find

The third number

$\sf\huge\bold{\underline{\underline{{Solution}}}}$

Mean is the sum of all terms divided by the number of terms.

$\sf \boxed{ \bold { mean = \frac{sum \: of \: all \: terms}{no.of \: terms} }}$

Let us assume that the third number be 'x'

Two numbers are given 16 & 22 respectively.

and mean is also given which is 21 so,simply just put the values in the mean formula .

$\sf \longmapsto \: mean = \dfrac{16 + 22 + x}{3}$

$\sf \longmapsto \: 21 = \dfrac{38 + x}{3}$

Now,cross multiply to both sides:

$\sf \longmapsto38 + x = 21 \times 3$

$\sf \longmapsto38 + x = 63$

$\sf \longmapsto \: x = 63 - 38 = 25$

$\sf \bold{x = 25}$

Check

$\sf \longmapsto \dfrac{16 + 22 + x}{3} = 21$

$\sf \longmapsto \dfrac{38 + 25}{3}$

$\sf \longmapsto \dfrac{63}{3} = 21$