Some pupils took a Math test. Their average score was 77.3 marks. One of the pupils' scores was wrongly recorded as 79 marks instead of 97 marks. As a result, the average score was calculated as 76.8 marks. How many pupils sat for the test?
| |
If that pupil's score was 97 |
If that pupil's score was 79 |
| Number of pupils |
1 u |
1 u |
| Average score |
77.3 |
76.8 |
| Total score |
77.3 u |
76.8 u |
Difference in the scores due to being wrongly recorded
= 97 - 79
= 18
Difference in total scores of the pupils is due to the difference in the wrongly recorded score.
77.3 u - 76.8 u = 18
0.5 u = 18
1 u = 18 ÷ 0.5 = 36
Number of pupils = 36
Answer(s): 36
