Question

the mean of 5 number is 18 if one number is excluded then mean become 16 find the excluded number​

Answer 1

Answer:

it can be done by 2 way

Step-by-step explanation:

1.Mean =X = 18

No of observations = 5

Sum of observations = = 18 x 5 = 90

Let the excluded number be x

New Mean X' = 16

New number of observations = 4

New sum of observations = 16 x 4

= 64 which is equal to 90 - x

thus 90 - 64 = 26

2. Let no.be x

Mean=18

{X1 + x2+ ....+ x5} ÷5= 18

X1+ x2+ ....+ X3= 5×18 I.e.90-------------(1)

If one no. is excluded

New mean=16

(X1+x2+ X3 + x4)÷4=16

X1+ x2+ X3+ x4=16×4 i.e64----------------(2)

Subracting equation (2) from (1)

X1+ x2+ x3+ x4+ x5 -( X1+ x2+ x3+ x4)=90-64

x5=26

Answer 2

Given:

→ The mean of 5 numbers is 18 if one number is excluded their men is 16.

Find:

→ Find the excluded number.

Calculations:

→ Mean of five numbers = 18.

→ 5 × 18

→ 90 -----(1)

We know, one number is excluded.

→ 4 × 16

→ 64 -----(2)

Subtracting equation (1) with equation (2), we get:

→ 90 - 64

→ 26

Therefore, 26 is the excluded number.