A Certain Brass Alloy Contains 60% Copper , 34% Zinc, And 6% Lead. How Many Kg Of This Brass Alloy And Of Zinc Must Be Added To 20 Kg Of Lead To Produce A New Brass Alloy That Is 40% Zinc And 8% Lead.


Thanks

Currently Lead has 20 kg and is 6% of what total? 20 = 6% of X, X = 20/6% = 333.33 kg.

Currently Copper is 60% of 333.33 = 200 kg. Currently Zinc is 34% of 333.33 = 113.33 kg.

Let's add C kg of Copper and Z kg of Zinc. The new total will be (200 + C) + (113.33 + Z) + 20.

The Zinc will be 40% of the new total, and the Lead will be 8% of the new total:

Zinc: (113.33 + Z) = 40%[(200 + C) + (113.33 + Z) + 20]
Lead: 20 = 8%[(200 + C) + (113.33 + Z) + 20]

The above is two equations in two unknowns, which you should be able to solve for C and Z.