A pupil’s marks were wrongly entered as 83 instead of 63. Due to the average marks for the class got increased by half. The number of pupils in the class is___________?
A. 10
B. 20
C. 40
D. 73
Explanation:
Let there be x pupils in the class.
Total increase in marks = (x * 1/2) = x/2
x/2 = (83 – 63) => x/2 = 20 => x = 40