Question

please answer question number 21

Answer 1

Arihant class 10 maths sample paper 8

ok

let's see

here deviation means subtracting every observation or xi with a fix number

so

(X1+X2+X3..........xn)- n×50=-10........eq(1)

and

(X1+X2 +X3 ........xn)-46×n=70........(eq2)

ok

from (eq1)

we get

(X1+.......xn)=-10+50n

putting it in eq2

we get n =20

and X1+ X2 ....xn=990

then as mean is asked

mean =sum of all observation/number of observations

=X1+X2+.....Xn/n

=990/20

=49.5

thanks for asking the question

brainliest if your doubts are clear.

Answer 2

Hey there!

Answer:

49.5

Step-by-step explanation:

Given,

Sum of deviations of x₁, x₂, x₃.....xₙ measured from 50 is -10.

So, x₁ + x₂ + x₃ + .....+ xₙ = 50n - 10 .............(i)

And,

It is also given that:

x₁ + x₂ + x₃ +.......+xₙ = 46n + 70 .............(ii)

Now,

From Equation (i) and (ii):

50n - 10 = 46n + 70

50n - 46n = 70 + 10

4n = 80

n = 20.

Finding Mean:

Mean = (x₁ + x₂+....+x₂₀) / 20

         = (50 * 20 - 10) / 20 = (46 * 20 + 70)/ 20

         = 990 / 20

         = 49.5

Hope It helps You!