Question

Given that 24 carat gold is pure gold 18 carat gold is 314 gold and 20 carat gold is 5/6 gold. Find the ratio of the pure gold in 18 carat gold to the pure gold in 20 carat gold.

• A. $7:10$
• B. $5:10$
• C. $3:10$
• D. $9:10$

Answer 1

The correct option is D $9:10$

It is given that $24$ carat gold is pure, $18$ carat gold is $\frac{3}{4}$ and $20$ carat gold is $\frac{5}{6}$.

Now, to find the ration of any two numbers, we have to divide those numbers,

so, the ratio of pure gold in $18$ carat gold to $20$ carat gold is as follows:

$\frac{3}{4}:\frac{5}{6}=\frac{3}{4}÷\frac{5}{6}=\frac{\frac{3}{4}}{\frac{5}{6}}=\frac{3}{4}\times \frac{6}{5}=\frac{18}{20}=\frac{9}{10}=9:10\{\because \frac{1}{\frac{1}{x}}=\frac{x}{1}\}$

Hence, the ratio of the pure gold in $18$ carat gold to the pure gold in $20$ carat gold is $9:10$