Three numbers are in in the ratio of 3 : 4 : 6 and their product is 1944. The largest of these numbers is :

Answer: Option C

Let the numbers be 3x, 4x and 6x
Then,
$$\begin{array}{rl}& \iff 3x\times 4x\times 6x=1944\\ & \iff 72x^3=1944\\ & \iff x^3=27\\ & \iff x=3\end{array}$$
∴ Largest number = 6x = 18