Question
An alloy consists of 35% gold, 40% silver, and 25% copper.
How much gold should be added to 20 kg of the alloy so that the new alloy contains 50% gold?Solution
ATQ,
Quantity of the alloy = 20 kg
Quantity of gold in 20 kg alloy = (0.35 × 20) = 7 kg
Quantity of silver in 20 kg alloy = (0.40 × 20) = 8 kg
Quantity of copper in 20 kg alloy = (0.25 × 20) = 5 kg
Let the quantity of gold to be added be x kg.
According to the question,
Quantity of gold in the new alloy = (Quantity of silver + Quantity of copper)
(7 + x) = (8 + 5)
Or, x = 13 - 7 = 6
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