In a class, there are 54 students. (100/3)% of the number of students are boys and the rest are girls. The average score in mathematics of boys is 50% more than that of the girls. If the average score of all the students is 70, then what is the average score of the boys?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 90
Number of students in class = 54
number of boys = (100/3)% of students = 54/3 = 18
number of girls = 54 - 18 = 36
Let the average score of girls = 10x
and average score of boys = (10x × 150)/100 = 15x
average score of all students = 70
total score of all students = 54 × 70 = 3780
total score of boys = 15x × 18 = 270x
total score of girls = 10x × 36 = 360x
so, 270x + 360x = 3780
⇒x = 6
hence, average score of boys = 15x = 90