In a Coimbatore school, the mean weight of 30 boys works out to 48 kg from their grouped table and the mean weight of 20 girls works out to 43 kg from theirs. Find the combined mean weight of all 50 students.

Question

Accepted Answer

46. Combined mean = n_1 x_1 + n_2 x_2n_1 + n_2 = 30(48) + 20(43)/50 = 1440 + 860/50 = 2300/50 = 46 kg. "45.5" is the plain average of 48 and 43, ignoring the group sizes; "45" swaps the two weights (20 boys, 30 girls); "91" simply adds the two means.

In a Coimbatore school, the mean weight of 30 boys works out to 48 kg from their grouped table and the mean weight of 20 girls works out to 43 kg from theirs. Find the combined mean weight of all 50 students.

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