document.write( "Question 1036025: An ATM keypad has ten keys. A PIN code is entered
\n" ); document.write( "by pressing a sequence of four keys.
\n" ); document.write( "A bank changes the PIN
\n" ); document.write( "codes to a sequence of six
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\n" ); document.write( "PIN codes possible if a key
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\n" ); document.write( "once in a sequence. Discuss the increase in security
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Algebra.Com's Answer #650799 by Edwin McCravy(20055)\"\" \"About 
You can put this solution on YOUR website!
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document.write( "For a 4-digit code the number of possibilities is \r\n" );
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document.write( "10 choices for the first digit.\r\n" );
document.write( "10 choices for the second digit.\r\n" );
document.write( "10 choices for the third digit.\r\n" );
document.write( "10 choices for the fourth digit.\r\n" );
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document.write( "That's 104 = 10000 possible 4-digit PINs.\r\n" );
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document.write( "10 choices for the first digit.\r\n" );
document.write( "10 choices for the second digit.\r\n" );
document.write( "10 choices for the third digit.\r\n" );
document.write( "10 choices for the fourth digit.\r\n" );
document.write( "10 choices for the fifth digit.\r\n" );
document.write( "10 choices for the sixth digit.\r\n" );
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document.write( "That's 106 = 1000000 possible 4-digit PINs.\r\n" );
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document.write( "For a discussion of increased security of 6 digits over 4, \r\n" );
document.write( "go to this website:\r\n" );
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document.write( "https://www.intego.com/mac-security-blog/ios-9-boost-passcode-security/\r\n" );
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document.write( "Edwin
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