If $\frac{18}{\sqrt{x}}=2$, then the value of $x$ is
(A) 81
(B) 36
(C) 18
(D) 9
(E) 3
Since $\frac{18}{\sqrt{x}}=2$, then $\sqrt{x}=9$, because the number by which we must divide 18 to get 2 is 9 . Since $\sqrt{x}=9$, then $x=9^{2}=81$.

ANswer: (A)