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An alloy contains 40% of silver, 30% of copper, and 30% of nickel. How much silver (in kg) should be added to 25 kg of the alloy so that the new alloy contains 50% of silver?

An alloy contains 40% of silver, 30% of copper, and 30% of nickel. How much silver (in kg) should be added to 25 kg of the alloy so that the new alloy contains 50% of silver? Correct Answer 5

Shortcut Trick

Silver = 40%; Copper = 30%; Nickel = 30%

Let, the total weight of alloy = 100 units

So, the silver = 40 units

If we add 20 units silver then, alloy = (100 + 20) = 120 units

also, silver = 40 + 20 = 60 units

Now, silver is 50% of the alloy 

So, 100 units = 25 kg

⇒ 20 units = (25/100) × 20 = 5 kg

∴ A total of 5 kg silver (in kg) should be added to 25 kg of the alloy so that the new alloy contains 50% of silver.

⇒ 20 + 2a = 25 + a

⇒ 2a - a = 25 - 20

⇒ a = 5

∴ A total of 5 kg silver (in kg) should be added to 25 kg of the alloy so that the new alloy contains 50% of silver.

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