the average marks ( out of 100) of boys and girls in an examination are 70 and 73 respectively. if the average marks of all the students in the exams is 71, then find the ratio of boys to the number of girls??

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the average marks ( out of 100) of boys and girls in an examination are 70 and 73 respectively. if the average marks of all the students in the exams is 71, then find the ratio of boys to the number of girls??

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the average marks ( out of 100) of boys and girls in an examination ar...

Let the number of boys and girls be x and yrespectively.

We know that, Sum of observations = Mean � Number of observations

Given, Mean marks of boys in the examination = 70

∴ Sum of marks obtained by boys in the examination = 70 � x = 70x

Given, Mean marks of girls in the examination = 73

∴ Sum of marks obtained by girls in the examination = 73 � y = 73y

Given, Mean marks of all students in the examination = 71

∴ Sum of marks obtained by all students in the examination = 71 (x + y)

Sum of marks obtained by all students in the examination

= Sum of marks obtained by boys in the examination + Sum of marks obtained by girls in the examination

∴ 71 (x + y) = 70x + 73y

⇒ 71x + 71y = 70x + 73y

⇒ 71x – 70x = 73y – 71y

⇒ x = 2y

⇒ x : y = 2:1

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the average marks ( out of 100) of boys and girls in an examination are 70 and 73 respectively. if the average marks of all the students in the exams is 71, then find the ratio of boys to the number of girls?? for Class 9 2024 is part of Class 9 preparation. The Question and answers have been prepared according to the Class 9 exam syllabus. Information about the average marks ( out of 100) of boys and girls in an examination are 70 and 73 respectively. if the average marks of all the students in the exams is 71, then find the ratio of boys to the number of girls?? covers all topics & solutions for Class 9 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for the average marks ( out of 100) of boys and girls in an examination are 70 and 73 respectively. if the average marks of all the students in the exams is 71, then find the ratio of boys to the number of girls??.

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