document.write( "Question 550228: in how many ways can 100 be written as the sum of two numbers,whose HCF is 1? answer choices 40,20,44,none.. \n" ); document.write( "
Algebra.Com's Answer #358729 by JBarnum(2146)\"\" \"About 
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50+50=100
\n" ); document.write( "hcf=50
\n" ); document.write( "we know they have to all be odd so 2 cant be a possible factor
\n" ); document.write( "1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 77 79 81 83 85 87 89 91 93 95 97 99
\n" ); document.write( "below i pointed out the prime numbers
\n" ); document.write( "\"1\" \"3\" \"5\" \"7\" 9 \"11\" \"13\" 15 \"17\" \"19\" 21 \"23\" 25 27 \"29\" \"31\" 33 35 \"37\" 39 \"41\" \"43\" 45 \"47\" 49 51 \"53\" 55 57 \"59\" \"61\" 63 65 \"67\" 69 \"71\" \"73\" 75 77 \"79\" 81 \"83\" 85 87 \"89\" 91 93 95 \"97\" 99
\n" ); document.write( "there are 25 odd prime numbers from 1 to 100
\n" ); document.write( "adding the corrisponding numbers to make 100 have proven to have a few duplicates or an HCF higher than 1 as shown below:\r
\n" ); document.write( "\n" ); document.write( "(1) 51+49=100
\n" ); document.write( "hcf=1
\n" ); document.write( "find all the prime numbers from 1 to 100
\n" ); document.write( "(2) 1+99 hcf is 1
\n" ); document.write( "2 is prime but 2 and 98 have hcf of 2
\n" ); document.write( "(3) 3+97 hcf is 1
\n" ); document.write( " 5+95 hcf is 5
\n" ); document.write( "(5) 7+93 hcf is 1
\n" ); document.write( "(6) 11+89 hcf is 1
\n" ); document.write( "(7) 13+87 hcf is 1
\n" ); document.write( "(8) 17+83 hcf is 1
\n" ); document.write( "(9) 19+81 hcf is 1
\n" ); document.write( "(10) 23+77 hcf is 1
\n" ); document.write( "(11) 29+71 hcf is 1
\n" ); document.write( "(12) 31+69 hcf is 1
\n" ); document.write( "(13) 37+63 hcf is 1
\n" ); document.write( "(14) 41+59 hcf is 1
\n" ); document.write( "(15) 43+57 hcf is 1
\n" ); document.write( "(16) 47+53 hcf is 1
\n" ); document.write( "______________
\n" ); document.write( "53+duplicate
\n" ); document.write( "59+duplicate
\n" ); document.write( "(17) 61+39 hcf is 1
\n" ); document.write( "(18) 67+33 hcf is 1
\n" ); document.write( "71+duplicate
\n" ); document.write( "(19) 73+27 hcf is 1
\n" ); document.write( "(20) 79+21 hcf is 1
\n" ); document.write( "83+duplicate
\n" ); document.write( "97+duplicate
\n" ); document.write( "---------------
\n" ); document.write( "i count (20) different ways
\n" ); document.write( "if you were to flip them as in a+b to b+a if that counts as a different way then there are 40 ways\r
\n" ); document.write( "\n" ); document.write( "hmmm just went back over this, accidently counted the 5 thisone i made number 4 so theres only 20 or a possible 40 if numbers were reversed
\n" ); document.write( "(4)9+91=100
\n" ); document.write( "9=1 3 9
\n" ); document.write( "91= 1 7 13
\n" ); document.write( "hcf is 1
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