The average mark scored by 8 boys is 72. If the scores of three girls are also included, the average marks increase by 3. The average marks scored by the three girls are:
Show answer & explanation
Correct answer: B
Explanation
The correct answer is option 2 i.e. 83
Let's assume that the total marks scored by the 8 boys are T.
Therefore, the average marks scored by the 8 boys are:
72 = T/8
T = 72 x 8
T = 576
Now, let's assume that the total marks scored by the 8 boys and the 3 girls are S.
Therefore, the average marks scored by all 11 students are:
72 + 3 = S/11
S = 11 x 75
S = 825
To find the average marks scored by the 3 girls, we can subtract the total marks scored by the 8 boys from the total marks scored by all 11 students and then divide by 3:
Average marks scored by 3 girls = (Total marks scored by 11 students - Total marks scored by 8 boys) / 3
= (825 - 576) / 3
= 249 / 3
= 83