UPSC Prelims 2015·CSAT·Quantitative Aptitude·Arithmetic

An automobiles owner reduced his monthly petrol consumption when the prices went up. The price-consumption relationship is as follows: Price (in Rs. Per litre) 40 50 60 75 Monthly consumption (in litres) 60 48 40 30 If the price goes up to Rs. 80 per litre, his expected consumption (in litres) will be

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Last updated 23 May 2026, 3:31 pm IST
  1. A30Correct
  2. B28
  3. C26
  4. D24

Explanation

The correct answer is A) 30. Here's a brief explanation: 1. **Observe the trend:** The data shows that as the price of petrol increases, the monthly consumption decreases (60 -> 48 -> 40 -> 30 litres). This is consistent with an owner reducing consumption when prices go up. 2. **Identify a potential minimum:** The last recorded consumption is 30 litres when the price is Rs. 75. In real-world scenarios, individuals often have a minimum essential consumption for goods like petrol (e.g., for commuting, essential errands). Once this minimum is reached, further price increases may not lead to further reductions in quantity consumed because the demand becomes perfectly inelastic at that point. 3. **Infer expected consumption:** If 30 litres represents this minimum essential consumption for the owner, then even if the price increases further to Rs. 80 per litre, the owner is unlikely to reduce consumption below this essential level. Therefore, the expected consumption would remain 30 litres. **Analysis of options:** * **A) 30:** This option implies that 30 litres is the minimum essential consumption, and further price increases won't lead to further reduction. This is a plausible economic behavior. * **B) 28, C) 26, D) 24:** These options would imply a further reduction in consumption. While a reduction is generally expected with a price increase, the concept of a minimum essential consumption suggests a floor beyond which reduction is not feasible. The pattern in the given data doesn't follow a simple linear or proportional decrease that would consistently lead to these lower values. For instance, if the owner were to maintain the expenditure of Rs. 2250 (which was the expenditure at P=75, C=30), then at P=80, consumption would be 2250/80 = 28.125 litres (close to 28). However, the initial expenditure was Rs. 2400, and the drop to Rs. 2250 at P=75 is better explained by hitting a consumption minimum of 30 litres, rather than a fixed expenditure cap. If 30 litres is the minimum, the owner would maintain it even if it means spending Rs. 2400 (80 * 30) again.
Quantitative Aptitude: An automobiles owner reduced his monthly petrol consumption when the prices went up. The price-consumption relationship

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