Question

R 3. The mean of 4 numbers is 8. Three of the numbers add up to 22. What is the last number?​

Answer 1

Solution :

let the last number be x

we know,

$\boxed{mean = \frac{sum \: \: of \: \: all \: \: observations}{number \: \: of \: \: observations} }$

So,

$\hookrightarrow \: 8 = \dfrac{22 + x}{4}$

$\hookrightarrow \: 8 \times 4 = 22 + x$

$\hookrightarrow \: 32 = 22 + x$

$\hookrightarrow \: x = 32 - 22$

$\hookrightarrow \: x = 10$

therefore, the last number is 10.