document.write( "Question 370132: In a string of length 9 with elements being a, b or c. How many strings will contain at least 6 b’s? \n" ); document.write( "
Algebra.Com's Answer #263896 by edjones(8007)\"\" \"About 
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expand(b+a+c)^9
\n" ); document.write( "1 b^9
\n" ); document.write( "2*9 b^8...
\n" ); document.write( "2*36+72 b^7...
\n" ); document.write( "2*84+252*2 b^6...
\n" ); document.write( "-------add
\n" ); document.write( "835 strings will contain at least 9 b's.
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