Question

the average marks of 28 students in mathematics was 50. 8 students left the school,then this average increased by 5 . what is the average of marks obtained by the students who left the school.

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Answer 1

Answer:

The average of marks obtained by the students who left the school is 37.5.

Given:

The average marks of 28 students in mathematics was 50. 8 students left the school, then this average increased by 5.  

To find:

The average of marks obtained by the students who left the school.

Solution:

Average = $\frac{sum of the'n'terms}{n}$

Let n be the number of students

Average marks of 28 students = 50

50 =$\frac{x}{28}$

x = 1400  … (1)

Average marks of 20 students = 55

55 =$\frac{y}{20}$

y = 1100 …(2)

The marks of of 8 students = 1400 – 1100 = 300

Average marks = $\frac{300}{8}$ = 37.5

Result:

37.5 is the average of marks obtained by the students who left the school.