How rare is finding a raikou on the first patch of grass ?

Question

I just finished morty's gym and went to the next gym right ? and I went to go grind on the first patch of grass, but suddenly, this lvl 40 thunder tiger was like, lemme kill this mf on the FIRST PATCH OF GRASS, and I just realized I only have like regular pokeballs, what do I do ???

Note: The game is SoulSilver

Comments

Which game? HGSS or GSC?

 thank you for the edit!

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I FOUND A FREAKING ENTEI ON THE FIRST PATCH OF GRASS

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How many places can a roaming Pokemon appear in HGSS? The answer should be 25% divided by that number.

Answer 1

Edit: My previous answer was both wrong and miscalculated. But since the answer is already there and no one post a new one I edited mine.

There are 16 Pokemon numbered route (route 29 to 46, ignore route 40 and 41) where you can encounter Raikou/Entei.
1 in 16 chance of it roaming to your first route after Morty's gym x 25% chance of that first encounter being Raikou => 1/16 * 1/4 = 0.015625. So 1.5625%.

Comments

How did you get these numbers? 1 in 20 (5%) x 25% is 1.25%, not 6.25%.

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Are you sure Raikou can't be found in places that aren't numbered routes, like Ruins of Alph or National Park?

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PokeFinder shows they only appear on Johto routes, and not on Route 40, 41, 47 or 48.

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So are there 16 places where it can appear? Or can they appear in places that aren't numbered routes?

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Yep they appear on 16 numbered routes and nowhere else.