document.write( "Question 798721: Most photocopiers can reduce the size an image by a maximum of 64% of the original dimensions how many reductions at the maximum setting would it take to reduce an image to less than 10% of its original dimensions\r
\n" ); document.write( "\n" ); document.write( "I did it logically and I got a answer of 6
\n" ); document.write( "But I prefer to do it algebraically using the geometric sequence formula
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Algebra.Com's Answer #482527 by KMST(5328)\"\" \"About 
You can put this solution on YOUR website!
With each reduction, the previous dimensions get multiplied by \"0.64=64%2F100=%2264%25%22\".
\n" ); document.write( "With \"n\" reductions the original dimensions will be multiplied times \"0.64%5En\",
\n" ); document.write( "and they will end up being multiplied times \"%220.10%22=10%2F100=%2210+%25%22\".
\n" ); document.write( "So \"0.64%5En%3C0.10\" is our equation\r
\n" ); document.write( "\n" ); document.write( "We could say that thew original length would be \"b%5B0%5D\",
\n" ); document.write( "and the length of the nth reduction would be \"b%5Bn%5D=b%5B0%5D%2A0.64%5En\".
\n" ); document.write( "Then we could write that a 10% reduction would reduce \"b%5B0%5D\" to \"b%5B0%5D%2A0.1\",
\n" ); document.write( "and write \"b%5B0%5D%2A0.64%5En%3Cb%5B0%5D%2A0.1\" --> \"0.64%5En%3C0.10\"
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\n" ); document.write( "From there we can
\n" ); document.write( "either start calculating powers of 0.64 until we get to less than 0.1,
\n" ); document.write( "or use logarithms.
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\n" ); document.write( "Calculating powers:
\n" ); document.write( "\"0.64%5E2=0.4096\"
\n" ); document.write( "\"0.64%5E3=0.262144\"
\n" ); document.write( "\"0.64%5E4=0.167772\"
\n" ); document.write( "\"0.64%5E5=0.107374\"
\n" ); document.write( "\"0.64%5E6=0.0687194\"
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\n" ); document.write( "Using logarithms:
\n" ); document.write( "\"0.64%5En%3C0.10\" --> \"log%280.64%5En%29%3Clog%280.10%29\" --> \"n%2Alog%280.64%29%3C-1\" --> \"n%2Alog%280.64%29%3C-1\"
\n" ); document.write( "\"log%280.64%29=approximately\"\"-0.19382%3C0\"
\n" ); document.write( "Dividing both sides of the inequality by a negative number, the inequality sign reverses, so
\n" ); document.write( "\"n%2Alog%280.64%29%3C-1\" --> \"n%3E-1%2Flog%280.64%29=approximately\"\"5.16\"
\n" ); document.write( "Since we need an integer \"n\", we need \"n%3E=6\"\r
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