Question

If an alloy of metal is made with 45% nickel, 25% copper and rest contain zinc. Find the weight of zinc present if the given alloy material weighs about 3 kg.

Answer 1

Hint: We have an alloy of metal with different percentages of metals present in it. We first find the percentage of zinc metal present in the metal alloy. We use this percentage of zinc to calculate the weight of zinc present in 3 kg of alloy.

Complete step-by-step answer:
Given that we have an alloy of metal which is made with 45% nickel, 25% copper and rest contain zinc. We need to find the weight of zinc present in 3 kg alloy.
First, we find the percentage of zinc present in metal alloy.
We know that the total percentage of material present in any material is equal to 100%.
We have metals nickel, copper and zinc constituting the 100% of metal alloy.
So, % of nickel + % of copper + % of zinc = 100%.
Substituting the percentage values given in the problem, we get
45% + 25% + % of zinc = 100%.
70% + % of zinc = 100%.
% of zinc = 100% - 70%.
% of zinc = 30%.
We have got 30% of zinc present in metal alloy.
Now we need to find the weight of zinc present in 3 kg of metal alloy.
We know that x% of y is defined as ‘x’ parts per hundred multiplied to y i.e., x% of y = $ \dfrac{x}{100}\times y $ .
We use this equation to find the weight of zinc.
Weight of zinc = 30% of 3kg of metal alloy
Weight of zinc = $ \dfrac{30}{100}\times 3 $ .
Weight of zinc = $ \dfrac{90}{100} $ .
Weight of zinc = 0.9kg.
∴ The weight of the zinc present in 3 kg of metal alloy is 0.9kg.

Note: Here we should multiply 30 with 3 to find the weight of zinc as % is defined as parts per 100. We can solve this problem even without finding the percentage of zinc. We solve for the weight of nickel and copper present in metal alloy and subtract it from the total weight of alloy.