First post:
The two letters that appear twice in the word BRILLIANT are I and L. The probability that I choose an I is \(\frac{1}{9}\), and the probability that I pick another I right after is 1/8 (as I already picked a letter, so there is one less to pick from). So the probability of picking two I's is \(\frac{1}{9}*\frac{1}{8}=\frac{1}{72}\), and the same goes for L too, so the probability of picking the same two letters in a row is \(\frac{2}{72}=\boxed{\frac{1}{36}}\)
Edited:
The two letters that appear twice in the word BRILLIANT are I and L. The probability that I choose an I is \(\frac{2}{9}\) (2 I's to pick from) , and the probability that I pick another I right after is 1/8 (as there is only one "I" left to pick, and there are now only 8 letter to pick from). So the probability of picking two I's is \(\frac{2}{9}*\frac{1}{8}=\frac{2}{72}=\frac{1}{36}\), and the same goes for L too, so the probability of picking the same two letters in a row is \(\frac{1}{36}+\frac{1}{36}=\boxed{\frac{1}{18}}\)
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