Two chairs and three tables cost Rs 1025, while three chairs and two tables cost Rs 1100. Determine the absolute difference between the cost of one table and one chair.
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ARs. 75
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BRs. 35
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CCannot be determined
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DRs. 125
Answer
Correct Answer: Rs. 75
Explanation
Introduction:Linear pairs of purchases create a system of two equations in two unknowns. Often, adding or subtracting the equations directly isolates a clean expression for either the sum or difference of unit prices.
Given Data / Assumptions:
- 2C + 3T = 1025 (C = price of a chair, T = price of a table)
- 3C + 2T = 1100
Concept / Approach:Subtract the equations to eliminate one variable and isolate the difference between T and C. We are asked for |T - C|, the absolute difference.
Step-by-Step Solution:(3C + 2T) - (2C + 3T) = 1100 - 1025C - T = 75Therefore, T - C = -75, and |T - C| = 75
Verification / Alternative check:Optionally solve fully. From C - T = 75 and 2C + 3T = 1025, substitute C = T + 75 to get 2(T + 75) + 3T = 1025, so 5T + 150 = 1025, hence T = 175 and C = 250. The difference is 75, matching the result.
Why Other Options Are Wrong:
- Rs. 35 and Rs. 125: not supported by the equations.
- Cannot be determined: incorrect because we have two independent equations for two unknowns.
Common Pitfalls:
- Adding rather than subtracting, which does not isolate the difference efficiently.
- Computational slip when substituting back to check values.
Final Answer:Rs. 75