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48.Mean age of 6 boys is 12 years andmean of 9 girls is 10 years. What isthe mean age, in years, of all theseboys and girls taken together ?(A) 10.8 (B) 11(C) 10(D) 10.5

Answer»

Mean = sum of all observations / number of observations

Given,Mean age of 6 boys is 12 yrs12 = sum of age of 6 boys/6sum of age of 6 boys = 12*6 = 72

Mean age of 9 girls is 10 yrs10 = sum of age of 9 girls/9sum of age of 9 girls = 10*9 = 90

Now, total sum of age of 6 boys and 9 girls = 72 + 90 = 162

Mean of 6 boys and 9 girls = 162/15 = 10.8

(A) is correct option



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