document.write( "Question 943417: How many four-letter arrangements can be made using the letters {a, b, c, d, e} if repetitions are allowed, but no letter may follow itself? \n" ); document.write( "
Algebra.Com's Answer #575320 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "1. Choose the middle (3rd) letter any of 5 ways.\r\n" );
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document.write( "2. Choose the 2nd letter any of 4 ways, (as any letter besides the letter you\r\n" );
document.write( "   chose for the 3rd letter).\r\n" );
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document.write( "3. Choose the 1st letter any of 4 ways, (as any letter besides the letter you\r\n" );
document.write( "   chose for the 2nd letter).\r\n" );
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document.write( "4. Choose the 4th letter any of 4 ways, (as any letter besides the letter you\r\n" );
document.write( "   chose for the 3rd letter). \r\n" );
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document.write( "5. Choose the 5th letter any of 4 ways, (as any letter besides the letter you\r\n" );
document.write( "   chose for the 4th letter).\r\n" );
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document.write( "Answer = 5󫶘󫶘 = 1280\r\n" );
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document.write( "Edwin
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