Some pupils took a Math exam. Their average score was 79.1 marks. One of the pupils' scores was wrongly recorded as 69 marks instead of 96 marks. As a result, the average score was calculated as 78.6 marks. How many pupils sat for the exam?
|
If that pupil's score was 96 |
If that pupil's score was 69 |
Number of pupils |
1 u |
1 u |
Average score |
79.1 |
78.6 |
Total score |
79.1 u |
78.6 u |
Difference in the scores due to being wrongly recorded
= 96 - 69
= 27
Difference in total scores of the pupils is due to the difference in the wrongly recorded score.
79.1 u - 78.6 u = 27
0.5 u = 27
1 u = 27 ÷ 0.5 = 54
Number of pupils = 54
Answer(s): 54