Question

The mass percent of gold in a sample of 24 carat gold is 100. What is its mass percent a sample of 18 carat gold?

• A. 65
• B. 75
• C. 85
• D. 95

Answer 1

The correct option is B

75

Explanation for correct option

Option B): Mass percentage

The mass percentage of a component can be calculated if the total mass and the mass of the component are known. It is otherwise called weight percent.

This can be solved using the unitary method.

$\begin{array}{rcl}24\mathrm{carat}& =& 100\%\\ 1\mathrm{carat}& =& \frac{100}{24}\\ \mathrm{So},18\mathrm{carat}& =& \frac{100}{24}\times 18\\ & =& 75\%\end{array}$

Explanation for incorrect options

From the unitary method it is clear that the answer is 75%. Remaining options A, C and D are incorrect.

So, option (B) is correct. The mass percent of the sample of 18-carat gold is 75 %.