3. Washington County includes six towns that need emergency ambulance service. Because of the proximity of some of the towns, a single station may serve more than one community.

The stipulation is that the station must be within 15 minutes of driving time from the towns it serves. The table below gives the driving times in minutes among the six towns.

Time in minutes from i to j

:s2 I 2 3 4 5 6 1 0 23 14 18 10 32 2 23 0 24 13 22 11 3 14 24 0 60 19 20 4 18 13 60 0 55 17 5 10 22 19 55 0 12 6 32 11 20 17 12 0