Question

The mean of first 8 observation is 18 and the mean of last 8 observations is 20 . if mean of all 15 observation is 19. find eight observation

Answer 1

FIRST 8 OBSERVATION = 8×18= 144

LAST 8 OBSERVATION = 8×20 = 160

16 OBSERVATION = 304
15 OBSERVATION IS
15×19 = 285

8 OBSERVATION = SUM OF 16 OBSERVATION -15 OBSERVATION

THEN

= 304 -285 = 19 ANSWER

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