Question

The mean of 8 numbers is 25. If 5 is subtracted from each number, what will be the new mean ?

• A. 10
• B. 20
• C. 30
• D. 40

Answer 1

The correct option is B 20

$\Rightarrow$ Taking the 8 numbers as $a,b,c,d,e,f,x,y.$

$\Rightarrow$ Here, mean of above numbers is $25.$

$\therefore \frac{a+b+c+d+e+f+x+y}{8}=25\to \left(1\right)$

$\Rightarrow$ If we subtract 5 from each number we get,

$=\frac{a-5+b-5+c-5+d-5+e-5+f-5+x-5+y-5}{8}$

$=\frac{a+b+c+d+e+f+x+y}{8}-\frac{40}{8}$ $\left[\begin{array}{c}From\\ eq10\end{array}\right]$

$=25-5$

$\therefore Mean=20$