Some pupils took a Math exam. Their average score was 75.6 marks. One of the pupils' scores was wrongly recorded as 89 marks instead of 98 marks. As a result, the average score was calculated as 75.3 marks. How many pupils sat for the exam?
| |
If that pupil's score was 98 |
If that pupil's score was 89 |
| Number of pupils |
1 u |
1 u |
| Average score |
75.6 |
75.3 |
| Total score |
75.6 u |
75.3 u |
Difference in the scores due to being wrongly recorded
= 98 - 89
= 9
Difference in total scores of the pupils is due to the difference in the wrongly recorded score.
75.6 u - 75.3 u = 9
0.3 u = 9
1 u = 9 ÷ 0.3 = 30
Number of pupils = 30
Answer(s): 30
