Question

The mean of 5 observation is 15. If the mean of first three observations is 14 and that of the last three is 17, find the third observation

Answer 1

Given that Mean of 5 observations is 15.

Therefore the sum of observations = 15 * 5 = 75.

Given that mean of the first 3 observations is 14.

Therefore the sum of first three observations = 14 * 3 = 42.

Given that mean of the last 3 observations is 17.

Therefore the sum of the last three observations = 17 * 3 = 51.


Hence,

The third observation = (42 + 51) - 75

                                     = 93 - 75

                                     = 18.


Hope this helps!

Answer 2

≡QUESTION≡

The mean of 5 observation is 15. If the mean of first three observations is 14 and that of the last three is 17, find the third observation.

                                                           

║⊕ANSWER⊕║

GIVEN

Mean of 5 observations = 15

∴ The sum of observations = 15 * 5

                                                =75

Mean of the first 3 observations = 14

∴ The sum of first three observations = 14 * 3

                                                                 = 42

Mean of the last 3 observations = 17

∴ The sum of the last three observations =17 * 3

                                                                        = 51

∴ The third observation =(42+51)−75

                                         =93−75

                                          = 18