In the sequence of five numbers $x$, $\qquad$ 3 , $\qquad$ 18 , each number after the second is obtained by multiplying the two previous numbers. The value of $x$ is
(A) $\frac{2}{3}$
(B) $\frac{3}{2}$
(C) 1
(D) -9
(E) -1
Since each number after the second is the product of the previous two numbers, then the 18 in the fifth position is the product of the 3 and the number in the fourth position. Thus, the number in the fourth position is 6.

So the sequence now reads, $x, \ldots, 3,6,18$.

Using the rule, 6 equals the product of 3 and the number in the second position. Thus, the sequence reads $x, 2,3,6,18$.

This tells us that $2 x=3$ or $x=\frac{3}{2}$.

Answer: (B)