A student's mark was wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by 1/2. What is the number of students in the class? Choose the correct choice from the following answers
A) 20  B) 30  C) 10  D) 40  E) 50
Let the total number of students = x   The average marks increased by 1/2 due to an increase of   83 - 63= 
<gadget id="calculator">  83 - 63</gadget>
<output>20</output>
20 marks.   But total increase in the marks= (1/2)x=x/2   Hence we can write as   x/2=20   ⇒x=20×2=40   Answer is 40.
<result>D</result>
A student's mark was wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by 1/2. What is the number of students in the class?