Question

John's marks were wrongly entered as 83 instead of 63. If the average marks calculated for the whole class increased by half, then find the number of students in the class.

Answer 1

The total number of students in the class are 40.

Let the number of students in the class be x.

Given, increase in average marks for the whole class is 50% and the marks were wrongly entered as 83 instead of 63.

              ⇒ x/2 = 83-63

              ⇒ x/2 = 20

              ⇒ x = 2(20)

              ⇒ x = 40

       

Answer 2

The number of students in the class is 40.

Step-by-step explanation:

We are given that John's marks were wrongly entered as 83 instead of 63.

If the average marks calculated for the whole class increased by half, we have to find the number of students in the class.

Let the total number of student in class be  $x$.

Now, we are given the increase in average marks of whole class = $\frac{1}{2}$

So, increase in total marks of all students =  $x\times \frac{1}{2}$

                                                                     =  $\frac{x}{2}$

But, it is stated that John's marks were wrongly entered as 83 instead of 63,which means the increase in marks is = 83 - 63 = 20 marks

Therefore,  $\frac{x}{2} = 20$

                   x = 40 students.

Hence, the number of students in the class is 40.