Math, asked by cheyanne1889, 1 year ago

the mean of 25 observations is 18. the mean of first 12 is 14 and the mean of last twelve is 17. find the thirteenth result

Answers

Answered by harvinder6
17

sum \: of \: 25 \: observations = 18 \times 25 = 450 \\ sum \: of \:1st \: 12 observations \ = 12 \times 14 = 168 \\ sum \: of \: last \: 12 \: observations = 12 \times 17 = 204 \\ 13th \: observation = 450 - (168 + 204) \\  = 450 - 372 \\  = 78
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