In what ratio should pulses costing Rs. 15/kg and Rs. 20/kg be mixed to get a mixture worth Rs. 16.50/kg?
Aptitude
Alligation or Mixture
Difficulty: Easy
Choose an option
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A7 : 3
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B3 : 7
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C5 : 4
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D4 : 5
Answer
Correct Answer: 7 : 3
Explanation
Problem restatementFind the mixing ratio (cheaper : dearer) for a target mean price of Rs. 16.50 between Rs. 15 and Rs. 20.
Concept/ApproachUse alligation: Quantity ratio (cheaper : dearer) = (dearer − mean) : (mean − cheaper).
Step-by-step calculation Ratio = (20 − 16.50) : (16.50 − 15) = 3.50 : 1.50 = 7 : 3
Verification/AlternativeWeighted average check with 7 kg of Rs. 15 and 3 kg of Rs. 20: mean = (7×15 + 3×20)/10 = (105 + 60)/10 = 165/10 = 16.50.
Final Answer7 : 3