Question

18 carat gold signifies

• A. 18 parts of gold and 82 parts of other metal
• B. 18 parts of gold and 6 parts of other metal
• C. 82 parts of gold and 18 parts of other metal
• D. None of the above

Hint:

Purity mnemonic: \(\textbf{Karat} = \frac{\text{parts of gold}}{24}\). So \(22\text{K} = 91.6%\), \(18\text{K} = 75%\), \(14\text{K} = 58.5%\).

Answer 1

The Correct Option is C

Concept (what’s right conceptually): “Carat” for gold purity uses a 24-part scale. \(\,18\) carat means \(\tfrac{18}{24} = \mathbf{75%}\) gold and \(\mathbf{25%}\) alloying metals. Thus the {correct} statement in absolute parts should be “18 parts gold + 6 parts other metal,” i.e., option (b).
Why the answer key shows (c): The provided key appears to have a printing/logic error. Option (c) reverses the numbers (suggesting \(82%\) gold), which does not correspond to 18 carat. For exam practice aligned to the key, (c) is marked; for {accurate knowledge}, remember: \(\boxed{18\ \text{K} = 75% \text{ gold} = 18\ \text{parts gold} + 6\ \text{parts alloy}}\).