Question

the mean of three number is 12. the mean of another five number is 14. find out the mean of all the numbers

Answer 1

let sum of 3 numbers be x
Mean = sum of observations / total no. of
observations
12 = x / 3
x = 12×3
x = 36

let sum of another 5 numbers be y
Mean = sum of observations / total no. of
observations
14 = y / 5
y = 14×5
y = 70

Mean of all the numbers = sum of observations / total no. of
observations
= x + y / 8
= 36 + 70 / 8
= 106 / 8
= 53 /4 or 13.25