Directions: The following table gives the percentage of marks obtained by 7 students in 6 different subjects in an examination. Study the table and answer the questions based on it. Note: The numbers in the brackets give the maximum marks in each subject. | Student | Maths (150) | Chemistry (130) | Physics (120) | Geography (100) | History (60) | Computer Science (40) | |---|---|---|---|---|---|---| | Ayush | 90 | 50 | 90 | 60 | 70 | 80 | | Aman | 100 | 80 | 80 | 40 | 80 | 70 | | Sajal | 90 | 60 | 70 | 70 | 90 | 70 | | Rohit | 80 | 65 | 80 | 80 | 60 | 60 | | Muskan | 80 | 65 | 85 | 95 | 50 | 90 | | Tanvi | 70 | 75 | 65 | 85 | 40 | 60 | | Tarun | 65 | 35 | 50 | 77 | 80 | 80 | What was the aggregate of marks obtained by Sajal in all the six subjects ?

### Concept & Calculation The table provides the **percentage** of marks obtained, not the absolute marks. The absolute marks for a subject are calculated as: $$ \text{Marks} = \left( \frac{\text{Percentage}}{100} \right) \times \text{Maximum Marks} $$ ### Step-by-Step Solution 1. **Maths:** $90\%$ of $150 = \left(\frac{90}{100}\right) \times 150 = 135$ 2. **Chemistry:** $60\%$ of $130 = \left(\frac{60}{100}\right) \times 130 = 78$ 3. **Physics:** $70\%$ of $120 = \left(\frac{70}{100}\right) \times 120 = 84$ 4. **Geography:** $70\%$ of $100 = \left(\frac{70}{100}\right) \times 100 = 70$ 5. **History:** $90\%$ of $60 = \left(\frac{90}{100}\right) \times 60 = 54$ 6. **Computer Science:** $70\%$ of $40 = \left(\frac{70}{100}\right) \times 40 = 28$ 7. **Total Aggregate Marks:** $135 + 78 + 84 + 70 + 54 + 28 = 449$ ### Exam Strategy & Shortcut To calculate percentages like $90\%$ of $150$ mentally, simply multiply the non-zero digits ($9 \times 15 = 135$). Do this for all subjects and sum them up quickly: $135 + 78 + 84 + 70 + 54 + 28 = 449$. ### Common Pitfall Summing the percentages directly instead of converting them to absolute marks first. Remember that the percentages are based on different maximum marks, so they cannot be added together. ### Final Answer Therefore, the correct answer is **449**.