The average marks of 28 students in Mathematics was 50. 8 students left the school and then the average increased by 5. What is the average of marks obtained by the students who left the school?
The average marks of 28 students in Mathematics was 50. 8 students left the school and then the average increased by 5. What is the average of marks obtained by the students who left the school?
Explanation
Total marks of 28 students in Mathematics = 28 x 50 = 1400
New number of students = 28 - 8 = 20
New average of marks in Mathematics = 50 + 5 = 55
∴
Total marks of 20 students in Mathematics = 20 x 55 = 1100
∴
Total marks of 8 students who left the school = 1400 - 1100 = 300
∴
Average marks of these 8 students =
300/8 = 37.5