A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is :
Choose the correct option:  A) 45  B) 40  C) 39  D) 37  E) 38
Explanation:   Let there be x pupils in the class.   Total increase in marks = (x * 1/2) = x/2.   x/2 = (83 - 63) =&gt; x/2 = 20 =&gt; x = 40. Answer: 40
<result>B</result>
A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is :