Question

an alloy of copper and zinc contains 45% copper and rest of the zinc.find the weight of zinc in 20 kg of the alloy

Answer 1

First of all we need to find out how much 1% is worth and to do that we divide 2kg/100 = 0.02kg

1% = 0.02kg

Next we simply times that by 55 to find the total weight of zinc
55 x 0.02 = 1.1kg

and if you need the weight of the copper is 0.9kg