Average Score Of Boys In Examination Of School Is 71 And Of Girls Is 73

The average score of boys in an examination of a school is 71 and of girls is 73. The … boys between number of girls appeared in the…

Answers:

Let x̅1 and x̅2 be the average scores of boys and girls respectively and x̅ be the average of both boys and girls. Then

1 = 71, x̅2 = 73, x̅ = 71.8

∴    x̅ = (n11 + n22)/(n1 + n2)

⇒  71.8 = (n1 × 71 + n2 × 73)/(n1 + n2)

⇒ 71.8(n1 + n2) = 71n1 + 73n2

⇒ 0.8n1 = 1.2n2

⇒ 8n1 = 12n2

⇒ n1/n2 = 12/8 = 3/2

Here   n1 : n2 = 3 : 2