document.write( "Question 148725: Use either the fundamental counting principle or the permutation formulas (or both) to answer the following\r
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\n" ); document.write( "\n" ); document.write( "if repetition of digits is permitted?\r
\n" ); document.write( "\n" ); document.write( "The Board of Directors does not have assigned \r
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Algebra.Com's Answer #109078 by stanbon(75887) $\"\"$ $\"About$

You can put this solution on YOUR website!
Use either the fundamental counting principle or the permutation formulas (or both) to answer the following
\n" ); document.write( "How many seven-digit phone numbers can be formed if the first digit cannot be 0
\n" ); document.write( "and
\n" ); document.write( "repetition of digits is not permitted?
\n" ); document.write( "Ans:
\n" ); document.write( "1st digit: 9 ways
\n" ); document.write( "2nd digit: 9 ways
\n" ); document.write( "3rd to 7th digits: 8!/2! = 8*7*6*5*4*3 = 20160
\n" ); document.write( "Total 9^2*20160 = 1632960
\n" ); document.write( "--------------------------
\n" ); document.write( "if repetition of digits is permitted?
\n" ); document.write( "Ans: 9*10^6 = 9 million
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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