Some pupils took a Math mock exam. Their average score was 75.5 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 73.7 marks. How many pupils sat for the mock exam?
|
If that pupil's score was 96 |
If that pupil's score was 69 |
Number of pupils |
1 u |
1 u |
Average score |
75.5 |
73.7 |
Total score |
75.5 u |
73.7 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.
75.5 u - 73.7 u = 27
1.8 u = 27
1 u = 27 ÷ 1.8 = 15
Number of pupils = 15
Answer(s): 15