The total marks obtained by a student in Physics, Chemistry and Mathematics together is 120 more than the marks obtained by him in Chemistry. What is the average marks obtained by him in Physics and Mathematics together?

### Concept & Logic This problem requires basic algebraic translation. By converting the English sentence into a mathematical equation, variables will naturally cancel out, leaving exactly the sum needed to compute the average. $$Average = \frac{Sum\ of\ Observations}{Total\ Number\ of\ Observations}$$ ### Step-by-Step Solution * **Given:** The total marks in Physics, Chemistry, and Mathematics is 120 more than the marks in Chemistry alone. * **Calculation:** Let the marks be $P$, $C$, and $M$. Write the equation based on the given statement. * $P + C + M = C + 120$ * Subtract $C$ from both sides of the equation. * $P + M = 120$ * We need the average marks obtained in Physics and Mathematics together. * $Average = \frac{P + M}{2}$ * $Average = \frac{120}{2} = 60$ ### Exam Strategy & Shortcut Read the problem carefully: if total marks of 3 subjects are 120 more than Chemistry, it means the *other two* subjects (Physics and Math) must perfectly sum to that "extra" 120. If their sum is 120, the average of these two subjects is simply half of that sum, which is 60. ### Common Pitfall Students often assume "Cannot be determined" because the individual marks for Physics and Math are unknown. You don't need individual values to find an average if you have their combined sum. ### Final Answer **Therefore, the correct answer is 60.**