In a class of 75 students, there are 35 girls and rest are the boys. During the science class test, the total marks score by the boys is 30 more than the total marks score by the girls. The average marks of the class is 23.6 excluding 6 boys and 4 girls who are not present on the day of test. What is the average marks score by the boys?
In a class of 75 students, there are 35 girls and rest are the boys. During the science class test, the total marks score by the boys is 30 more than the total marks score by the girls. The average marks of the class is 23.6 excluding 6 boys and 4 girls who are not present on the day of test. What is the average marks score by the boys?
1). 23
2). 25
3). 24.5
4). 23.8
1 answers
Total number of students = 75
Number of girls in class = 35
Number of boys = Total students – number of girls = 75 – 35 = 40
Number of students who attempt the test = 75 – 6 – 4 = 75 – 10 = 65
Total marks score by 65 students = 65 × average marks of students = 65 × 23.6 = 1534
Let assume the total marks score by boys = x and total marks score by the girls = y
Total marks score by students = x + y
⇒ x + y = 1534 ----(1)
From the condition given in the question,
Total marks of boys = total marks of girls + 30
⇒ x = y + 30 ----(2)
Substitute the value of x from equation 2 in equation 1
⇒ y + 30 + y = 1534
⇒ 2y + 30 = 1534
⇒ 2y = 1534 – 30
⇒ y = 1534/2 = 752
Substitute the value of y in equation 2
Total marks score by boys = 752 + 30 = 782
Number of boys who attempt the exam = 40 – 6 = 34
∴ Average marks score by boys = 782/34 = 23