Question

The mean of the first 4 observations is 3, the next 3 observations is 2, and the mean of the last 3 observations is 5. What is the
mean of all the observations?​

Answer 1

Answer:

the last three is 17, Find the third observation.

Answer

⇒ It is given that Mean of 5 observations is 15.

∴ The sum of observations =15×5=75.

∴ It is given that mean of the first 3 observations is 14.

∴ The sum of first three observations =14×3=42.

⇒ Given that mean of the last 3 observations is 17.

∴ The sum of the last three observations =17×3=51

∴ The third observation =(42+51)−75

=93−75

=18