In the 8th class, consisting of 30 students, a Mathematics test was taken. 10 students had an average score of 90. The other students had an average score of 75. What is the average score of the whole class?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e. 80.
The first group consists of 10 students with an average score of 90
Total score of first group = 10 × 90 = 900
The second group consists of 30 − 10 = 20 students with an average score of 75
Total score of second group = 20 × 75 = 1500
Now,
Total score of the whole class = 900 + 1500 = 2400
So,
Average score = Total score of whole class/Total number of students
Average score = 2400/30 = 80