document.write( "Question 1188291: In how many ways can 25 be expressed as the sum of three prime numbers?
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document.write( "A) 1 B) 3 C) 4 D) 5 E) 6 \n" );
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Algebra.Com's Answer #819342 by greenestamps(13200)![]() ![]() You can put this solution on YOUR website! \n" ); document.write( "Do some work on this yourself to find the answer. \n" ); document.write( "There is only one even prime number, 2. \n" ); document.write( "The sum of any two odd prime numbers is even. \n" ); document.write( "The desired sum of three prime numbers is 25, which is odd. \n" ); document.write( "Therefore, the sum of 25 must be using three odd primes. \n" ); document.write( "Note that, the way the problem is written, it is allowable for two of the three odd prime numbers to be the same. \n" ); document.write( "So...... \n" ); document.write( "(1) If the smallest of the three odd prime numbers is 3, then the sum of the other two must be 22. \n" ); document.write( "(2) If the smallest of the three odd prime numbers is 5, then the sum of the other two must be 20. \n" ); document.write( "(3) If the smallest of the three odd prime numbers is 7, then the sum of the other two must be 18. \n" ); document.write( "Clearly the smallest of the three odd prime numbers can't be 11 or more. \n" ); document.write( "So look for solutions in each of the three cases. Only simple addition is required. \n" ); document.write( " \n" ); document.write( " |