An alloy contains gold and silver in the ratio 5 : 8 and another alloy contains gold and silver in the ratio 5 : 3. If equal amount of both the alloys are melted together, then the ratio of gold and silver in the resulting alloy is?
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A113/108
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B105/103
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C108/115
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D103/113
Answer
Correct Answer: 105/103
Explanation
Step 1: Understand the composition of both alloys
- First alloy has gold and silver in the ratio 5 : 8
- Second alloy has gold and silver in the ratio 5 : 3
- Equal amounts of both alloys are mixed. Assume 1 unit each for simplicity.
Step 2: Express each alloy in terms of total parts and quantities
- First alloy has 5 + 8 = 13 parts
- Second alloy has 5 + 3 = 8 parts
Step 3: Calculate gold and silver content in each alloy (assuming LCM for equal total quantity)
- Take LCM of 13 and 8 = 104 (to equalize total mass of each alloy)
- Multiply first alloy’s ratio (5:8) by 8 ⇒ Gold = 5×8 = 40, Silver = 8×8 = 64
- Multiply second alloy’s ratio (5:3) by 13 ⇒ Gold = 5×13 = 65, Silver = 3×13 = 39
Step 4: Add gold and silver from both alloys
Total gold = 40 + 65 = 105 Total silver = 64 + 39 = 103
Step 5: Final ratio of gold and silver
Ratio = 105 : 103
Answer: 105 : 103
After melting equal quantities of both alloys, the resulting alloy contains gold and silver in the ratio 105:103.
This question is a good example of weighted average and ratio adjustment commonly used in alloys, mixtures, and metal preparation problems. Understanding how to normalize quantities using LCM makes such mixture questions easier and ensures proportional consistency in combining two different compositions.