DSSSB 6 September 2024
Non Nursing Subjects
Hard

In what ratio should sugar costing ₹52.5 per kg be mixed with sugar costing ₹17 per kg so that there is a profit of 12% on selling the mixture at ₹44.8 per kg?

Appeared in: DSSSB 6 September 2024

Explanation

  • First, calculate the cost price (CP) of the mixture using the selling price (SP) and profit percentage. The formula is CP = SP / (1 + Profit%/100).
  • Given SP = ₹44.8 and Profit = 12%, the CP = 44.8 / 1.12 = ₹40 per kg.
  • Next, apply the rule of alligation. This rule helps find the ratio of two ingredients when their individual costs and the mean cost of the mixture are known.
  • The ratio of the dearer sugar (costing ₹52.5) to the cheaper sugar (costing ₹17) is calculated as (Mean Price - Cheaper Price) : (Dearer Price - Mean Price).
  • Substituting the values: (40 - 17) : (52.5 - 40) = 23 : 12.5.
  • To convert this to a whole number ratio, multiply both sides by 2, which gives 46 : 25.

Why Other Options Were Wrong

  • Option B: This ratio is incorrect. It may result from a miscalculation in the alligation step or an error in calculating the cost price of the mixture.
  • Option C: This ratio is incorrect. It likely arises from calculation errors, such as incorrectly subtracting the values in the alligation formula.
  • Option D: This ratio is incorrect. Such a result could occur if the selling price was mistakenly used as the mean price in the alligation rule, or from other arithmetic mistakes.

Related Visual

An infographic visually demonstrating the rule of alligation. It should show the cost of the two ingredients at the top, the mean price in the center, and the arrows pointing do...
Clinical Relevance
  • Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mixtures and Alligation with Profit Percentage as background academic context rather than a clinical decision trigger.
  • This question tests quantitative aptitude, a skill essential for various competitive examinations, including those for nursing positions.
  • The ability to solve problems involving percentages, ratios, and mixtures is a measure of logical reasoning and analytical skills.
  • What if the mixture was sold at a loss of 10% instead of a profit? The cost price would be calculated as CP = 44.8 / (1 - 0.10) = 44.8 / 0.90 ≈ ₹49.78. This new CP would then be used in the alligation formula, leading to a different ratio.
How to Approach the Question
  • First, identify all the given values: the cost of the two types of sugar, the selling price of the mixture, and the profit percentage.
  • Recognize that the 'mean price' required for the alligation rule is the cost price (CP) of the mixture, not the selling price (SP).
  • Calculate the CP of the mixture by removing the profit from the SP using the formula: CP = SP / (1 + Profit%/100).
  • Set up the alligation diagram with the cost of the dearer item on one side, the cheaper item on the other, and the calculated mean price (CP) in the middle.
  • Perform the cross-subtraction: subtract the cheaper cost from the mean price, and subtract the mean price from the dearer cost.
  • The two results from the subtraction give the required ratio. Simplify the ratio to its simplest whole number form if necessary.
Concept Tested & Keywords
  • Concept Tested: Mixtures and Alligation with Profit Percentage
  • Stem keywords: ratio, sugar, costing, mixed, profit, selling mixture
  • Lead-in keywords: In what ratio

Question ID

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