Math Is Fun Forum

Assuming rain is frequent enough to keep him alive since he is not dead already.

The guy should immediately start the fire as far east  as possible to still be safe from the burning fire.

Then he can just collect items for building a shelter, traps, collecting rain water, and food containing seed(s) from the farthest west he can go and hoard it where his fire already burned.    He continues this until there is no room left between his burned land on the east and the approaching fire from the west.

Clear some scorched land until he reaches good soil, plant a garden, and live off of his collected food in the meantime. Any live animals on the island from west of his fire will eventually flee to his scorched land to the east, so he should trap some using his food (the only on the island) for bait.  Feed them just enough to stay alive until he is ready to eat them.  Then he can wait out the garden.