Question: 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 (1/2). The number of pupils in the class is:
[A].10
20
40
73
[A].
[B].
[C].
[D].
Answer: Option C
Explanation:
Let there be x pupils in the class.
| Total increase in marks = | x x | 1 | = | x | ||
| 2 | 2 |
| x | = (83 – 63) | x | = 20 x= 40. | |
| 2 | 2 |