1. **Stating the problem:** We have marks and their corresponding weights for five subjects. We want to calculate the weighted mean of the marks and compare it to the simple mean. 2. **Write down the data:** - Math: mark = 75, weight = 4 - English: mark = 80, weight = 2 - Physics: mark = 85, weight = 3 - Chemistry: mark = 78, weight = 3 - ICT: mark = 90, weight = 2 3. **Calculate the weighted mean:** The weighted mean formula is: $$\text{Weighted Mean} = \frac{\sum (\text{mark} \times \text{weight})}{\sum \text{weights}}$$ Calculate the numerator: $$75 \times 4 + 80 \times 2 + 85 \times 3 + 78 \times 3 + 90 \times 2 = 300 + 160 + 255 + 234 + 180 = 1129$$ Calculate the denominator: $$4 + 2 + 3 + 3 + 2 = 14$$ Therefore, $$\text{Weighted Mean} = \frac{1129}{14} = 80.64$$ (rounded to two decimal places) 4. **Calculate the simple mean:** Sum of marks: $$75 + 80 + 85 + 78 + 90 = 408$$ Number of subjects = 5 Simple mean: $$\frac{408}{5} = 81.6$$ 5. **Compare the two means:** The weighted mean is approximately 80.64, while the simple mean is 81.6. 6. **Observation:** The weighted mean takes into account the credit hours, giving more importance to subjects with higher weights. Because Math (75) had the highest weight (4) and is below the simple mean, the weighted mean is slightly lower than the simple mean.