Question

A certain alloy contains $5.25\% $ of copper. How much copper is there in a piece weighing $200$ pounds ?

Answer 1

Hint:The given question involves the concepts of percentages. This problem requires us to find a specific percentage of a given alloy weighing $200$ pounds. To solve this problem, we need to know how to calculate a specific percentage of a number. We can solve this problem by two methods. Such questions require accuracy in arithmetic.

Complete step by step answer:
So, we have,
Weight of the alloy as $200$ pounds .
Now, the percentage of the alloy as copper is $5.25\% $ .
So, the weight of copper in the alloy can be calculated by finding $5.25\% $ of $200$ pounds.
So, $5.25\% $ of $200$ can be calculated as:
$\dfrac{{5.25}}{{100}} \times 200$
Simplifying the calculations, we get,
$ \Rightarrow 5.25 \times 2$
Simplifying further, we get,
$ \Rightarrow 10.5$
Hence, $5.25\% $ of $200$ is $10.5$

So, the weight of cooper in $200$ pounds of alloy is $10.5$ pounds.

Note: Though we have a number of methods to solve this problem, it is better to workout with the above-mentioned method and after solving a number of problems in this model, one can consider the method involving the unitary method. Solving problems by the unitary method needs better understanding of the concept. While solving such a problem using a unitary method, we consider the given number as $100\% $ of itself and then then find out the desired percentage of the number. Work as many problems as possible to crack these types of problems in a limited time period.