Question

60 students of section A of class Xl obtained 40 mean in statistics ,40 students of section B obtained 35 mean marks in statistics for class Xl as a whole.

Answer 1

HEY MATE HERE IS YOUR ANSWER

$marks \: of \: class \: a\\ \frac{x1 + x2..........x60}{60} = 40 \\ x1 + x2 + .............x60 = 2400 - > 1 \\ marks \: of \: class \: b \\ \frac{y1 + y2 + y3.......y60}{60} = 35 \\ y1 + y2 + y3.......y60 = 2100 - > 2 \\ add \: 1and2 \\ x1 + x2....x60 + y1 + y2 + y3......y60 = 2100 + 2400 \\ x1 + x2 ....x60 + y1 + y2 + y3......y60 = total \: students \: of \: ix \: class \\ \frac{x1 + x2 + ....x60 + y1 + y2 + y3...y60}{120} = mean \\ \frac{4500}{120} = 37.5$

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