document.write( "Question 1203273: The letters of the word PROBABILITY are arranged at random. Find the number of arrangements where the two Is are separated. \n" ); document.write( "
Algebra.Com's Answer #838710 by greenestamps(13200)\"\" \"About 
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\n" ); document.write( "The comment from tutor @ikleyn is correct. In counting the number of arrangements with the two I's together, there is only one way to arrange those two I's, because they are the same letter.

\n" ); document.write( "The total number of arrangements is of 11 letters including 2 pairs. That number is \"%2811%21%29%2F%28%282%21%29%282%21%29%29\"

\n" ); document.write( "For the number of arrangements with the 2 I's together, treat them as a single unit.

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\n" ); document.write( "NO!... Then there are 10 items with one (other) pair; and the two I's in the unit can be arranged in either of 2 orders. This number is then \"%282%29%28%2810%21%29%2F%282%21%29%29\"

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\n" ); document.write( "Yes... Then there are 10 items with one (other) pair. the number of arrangements here is then \"%2810%21%29%2F%282%21%29\"

\n" ); document.write( "Subtract the second number from the first to get the number of arrangements in which the two I's are separated (i.e, not together).

\n" ); document.write( "You can do the actual calculations....

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