In a classroom consisting of boys and girls, the average marks obtained by the boys is 90. If the average of the whole class is 92, and the ratio of the number of boys to that of girls is 3 : 2, what is the average marks scored by the girls?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 95.
We know that,
Average = Sum of observations/Number of observations
Now,
Let the number of boys and girls be 3x and 2x respectively
Given that, the average mark of boys is 90
So, the total marks obtained by boys = 90 × 3x = 270x
The average marks obtained by boys and girls together is 92
So, the total marks obtained by the whole class = 92 × 5x = 460x
Now,
The total marks obtained by girls = 460x - 270x = 190x
The average marks obtained by girls = 190x/2x = 95
Hence, the average mark obtained by girls is 95