document.write( "Question 1124566: The average age of three girls is seventeen years four months. The average age of two of them is seventeen years three months. How old is the third girl? \n" ); document.write( "
Algebra.Com's Answer #740870 by Theo(13342)\"\" \"About 
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average age of all three girls is 17 years and 4 months.\r
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\n" ); document.write( "\n" ); document.write( "average age of two of the girls is 17 years and 3 months.\r
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\n" ); document.write( "\n" ); document.write( "what is the age of the third girl?\r
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\n" ); document.write( "\n" ); document.write( "if the average age of all three girls is 17 years and 4 months, then the total age of those three girls must be 3 * (17 years and 4 months) = 51 years and 12 months.\r
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\n" ); document.write( "\n" ); document.write( "if the average age of two of those girls is 17 years and 3 months, then the total age of those two girls must be 2 * (17 years and 3 months) = 34 years and 6 months.\r
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\n" ); document.write( "\n" ); document.write( "when you subtract the total age of all three of the girls from the total age of two of those girls, you get the age of the third girl.\r
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\n" ); document.write( "\n" ); document.write( "51 years and 12 months minus 34 years and 6 months results in 17 years and 6 months.\r
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\n" ); document.write( "\n" ); document.write( "that's the age of the third girl.\r
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