To find the overall mark of the 20 students, we first need to find the total marks for each group.
For Phil's group:
- Number of students: 12
- Mean mark: 76%
Total marks for Phil's group = 12 × 76% = 12 × 0.76 = 9.12.
For Paul's group:
- Number of students: 8
- Mean mark: 84%
Total marks for Paul's group = 8 × 84% = 8 × 0.84 = 6.72.
Now, to find the overall mark for the 20 students, we add the total marks from both groups:
Overall mark = 9.12 + 6.72 = 15.84.
Now, to find the overall mean mark, we divide the overall mark by the total number of students:
Overall mean mark =15.84/12 + 8 =15.84/20 = 0.792.
To express the overall mean mark as a percentage, we multiply by 100:
Overall mean mark = 0.792 × 100% = 79.2%.
So, the overall mark of the 20 students is 79.2%.
