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標題:

F3 Maths

發問:

An alloy contains 35% of zinc by weight, Some alloy A and pure zinc are melted to form a new alloy that weighs 400kg and contains 66.0625% of zinc by weight. What are the weights of alloy A and zinc needed to form the new alloy respectively ? (Give your answers correct to the nearest kg)

最佳解答:

Let m kg of alloy A is needed to form the new alloy. Then, weight of zinc needed to form the new alloy = (400 - m) kg Weight of zinc in the new alloy: (35%)m + (400 - m) = (66.0625%) x 400 0.35m + 400 - m = 264.25 0.65m = 135.75 m = 209 400 - m = 191 Weight of alloy A needed = 209 kg (nearest kg) Weight of zinc needed = 191 kg (nearest kg)

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