\[18;4;\ldots\]
\[a_{1} = 18;\ \ a_{2} = 4;\]
\[d = 4 - 18 = - 14.\]
\[a_{n} = - 38\]
\[a_{n} = a_{1} + d(n - 1)\]
\[- 38 = 18 - 14 \cdot (n - 1)\]
\[18 - 14n + 14 = - 38\]
\[- 14n = - 38 - 32\]
\[- 14n = - 70\]
\[n = 5.\]
\[Встретится,\ на\ 5\ месте.\]