UKMT Grey Kangaroo, 2016

Combinatorics Difficulty 2.0 Junior Find the answer United Kingdom

Four towns $P$ , $Q$ , $R$ and $S$ are connected by roads, as shown. A race uses each road exactly once. The race starts at $S$ and finishes at $Q$ . How many possible routes are there for the race?

(A) $10$ (B) $8$ (C) $6$ (D) $4$ (E) $2$

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