Some pupils took a Math mock test. Their average score was 79.3 marks. One of the pupils' scores was wrongly recorded as 68 marks instead of 86 marks. As a result, the average score was calculated as 78.8 marks. How many pupils sat for the mock test?
| |
If that pupil's score was 86 |
If that pupil's score was 68 |
| Number of pupils |
1 u |
1 u |
| Average score |
79.3 |
78.8 |
| Total score |
79.3 u |
78.8 u |
Difference in the scores due to being wrongly recorded
= 86 - 68
= 18
Difference in total scores of the pupils is due to the difference in the wrongly recorded score.
79.3 u - 78.8 u = 18
0.5 u = 18
1 u = 18 ÷ 0.5 = 36
Number of pupils = 36
Answer(s): 36
