Some pupils took a Math mock test. 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 77.3 marks. How many pupils sat for the mock test?
|
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 |
77.3 |
Total score |
79.1 u |
77.3 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 - 77.3 u = 27
1.8 u = 27
1 u = 27 ÷ 1.8 = 15
Number of pupils = 15
Answer(s): 15