The average mark of the students of a class in a particular exam is 80.

The average mark of the students of a class in a particular exam is 80. If 5 students whose average mark in that exam is 20 are excluded, the average mark of the remaining will be 92. Find the number of students who wrote the exam.

Quiz

30

Steps/Work

Let the number of students who wrote the exam be x.
Total marks of students = 80 x.
Total marks of (x - 5) students = 92(x - 5)
80x - (5 * 20) = 92(x - 5)
360 = 12x => x = 30

General Calculator / Auto Solver

The average mark of the students of a class in a particular exam is . If students whose average mark in that exam is are excluded, the average mark of the remaining will be . Find the number of students who wrote the exam.

30

Step by Step Solution

In order to solve problem, you must evaluate (n1 * n3 - n1 * n2) / (n3 - n0).

 n0 = 80 5 20 92
• (n1 * n3 - n1 * n2) / (n3 - n0)
• Evaluate n1 * n3 = 460

(460 - n1 * n2) / (n3 - n0)
• Evaluate n1 * n2 = 100

(460 - 100) / (n3 - n0)
• Evaluate 460 - 100 = 360

360 / (n3 - n0)
• Evaluate n3 - n0 = 12

360 / 12
• Evaluate 360 / 12 = 30

30
• The answer to the problem and the result of (n1 * n3 - n1 * n2) / (n3 - n0) is 30