Some pupils took a Math test. Their average score was 74.7 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 74.5 marks. How many pupils sat for the test?
| |
If that pupil's score was 98 |
If that pupil's score was 89 |
| Number of pupils |
1 u |
1 u |
| Average score |
74.7 |
74.5 |
| Total score |
74.7 u |
74.5 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.
74.7 u - 74.5 u = 9
0.2 u = 9
1 u = 9 ÷ 0.2 = 45
Number of pupils = 45
Answer(s): 45
