Question

In as school, average marks of three batches of 40, 50 and 60 students respectively is 45, 55 and
70. Find the average marks of all the students?

Answer 1

Answer:

Average marks of all students = 45+55+70 / 40+50+60 = 170/150= 17/15 = 1.133 marks.

Ans is approximately 1 mark.

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Answer 2

58.34 marks are the  average marks of all the students.

Explanation:

Given: Batches              Average Marks

           40 students    ⇒     45

           50 students   ⇒      55

           60 students   ⇒      70

Total number of students = 40 + 50 + 60 = 150

Average marks = total marks / total no. of students

     ∴ Total marks = total no. of students × Average marks

( for batch of 40 students ) total marks = 40 × 45 = 1800

( for batch of 50 students ) total marks = 50 × 55 = 2750

( for batch of 60 students ) total marks = 60 × 70 = 4200

Avrage marks of all the students = total marks / total no. of students

                                                         = 1800 + 2750 + 4200 / 150

                                                         = 8750 /150

                                                         = 58.34

∴ 58.34 marks are the  average marks of all the students.