There are ten different types.
I wanted Eri, Yakumo and Akira, so that means five out of ten of these were acceptable, a 50% chance. I bought one. IT WAS BIKINI MIKOTO FUCK. I walked right back into the store and bought a second one. IT WAS KAREN! Damn. I’m ok with Karen but somehow, she’s not my type.
So I actually got the worst possible combination actually. 5/10 x 4/9 = 2/9. I had a 22 percent chance of failing to get even ONE girl that I wanted. And I got this 22 percent.
The chances of getting one crappy chain (Mikotos, Sara, Tenma and Karen) and then one desired chain was 5/10 + 5/10 x 5/9 which is about 78 percent!! Or you could just take 100-22.
IT’S A FUCKING OMEN!! Actually, I should’ve just bought one more. Then the chances of not getting what I wanted would be very very slim. 5/10 + 5/10 x 5/9 + 5/10 x 4/9 x 5/8 = about 92 percent!!! Nobody fails at 92 percent!
Hmm but upon closer examination, the fact that I had already failed twice means that if I bought the 3rd one, my chances of getting a good keychain would actually be only 5/8, that is 62.5 percent, rather than 92 percent.
I thought this while on the way home. But then again, I’m probably getting the whole set upon my return to Singapore so less duplicates the better.