Previous in Probability and Statistics Next in Probability and Statistics
Question Number 25549 by pieroo last updated on 11/Dec/17
$$\mathrm{The}\:\mathrm{mean}\:\mathrm{weights}\:\mathrm{of}\:\mathrm{three}\:\mathrm{groups}\:\mathrm{of}\:\mathrm{students} \\ $$$$\mathrm{consisting}\:\mathrm{of}\:\mathrm{16},\:\mathrm{18}\:\mathrm{and}\:\mathrm{20}\:\mathrm{students}\:\mathrm{are}\:\mathrm{40}.\mathrm{5kg},\:\mathrm{42}.\mathrm{50kg} \\ $$$$\mathrm{and}\:\mathrm{45}.\mathrm{00kg}\:\mathrm{respectively}.\:\mathrm{What}\:\mathrm{is}\:\mathrm{the}\:\mathrm{mean}\:\mathrm{weight} \\ $$$$\mathrm{of}\:\mathrm{all}\:\mathrm{the}\:\mathrm{students}? \\ $$
Answered by Rasheed.Sindhi last updated on 11/Dec/17
$$\frac{\mathrm{40}.\mathrm{5}×\mathrm{16}+\mathrm{42}.\mathrm{5}×\mathrm{18}+\mathrm{45}×\mathrm{20}}{\mathrm{16}+\mathrm{18}+\mathrm{20}}\approx\mathrm{42}.\mathrm{83} \\ $$