306. Lightning Rod. A strong gust of wind broke the lightning rod's pole, causing its top to hit the ground 20 m from the base of the pole. The pole was repaired, but it broke again under a gust of wind, 5 m lower than before, and its top hit the ground 30 m from the base.

What is the height of the pole? In both cases, the broken part of the pole did not completely separate from the rest of it.