Question

The mean of 6 observation is 23 if one of the number is excluded the mean of remaining number is 20. Find the excluded number

Answer 1

hi,
it's easy....

mean=sum of observations / no. of observations
therefore,

mean x no. of observations=sum of observations

hence, sum of observations=6x23=138

let the no. excluded be 'x'

(138-x)/5=20
138-x=100
x=38

hence the excluded no. is 38

Answer 2

ANSWER...................,

The mean of 6 number = 23

The sum of 6 number = 6 × 23 = 138

If one number is excluded ,

Then mean of 5 number = 20

Sum of 5 number = 5 × 20 = 100

∴excluded number = 138 - 100 = 38