document.write( "Question 1055591: In a school 50% of the students are younger than 10, 1/20 are 10 years old and 1/10 are older than 10 but younger than 12, the remaining 70 students are 12 years or older. How many students are 10 years old? \n" ); document.write( "
Algebra.Com's Answer #670778 by ikleyn(52781)\"\" \"About 
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\n" ); document.write( "In a school 50% of the students are younger than 10, 1/20 are 10 years old and 1/10 are older than 10 but younger than 12,
\n" ); document.write( "the remaining 70 students are 12 years or older. How many students are 10 years old?
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document.write( "Let x = the total number of students in the school.\r\n" );
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document.write( "Then 0.5x are those who are younger than 10;       (1)\r\n" );
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document.write( "     0.05 are 19 years old;                        (2)\r\n" );
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document.write( "     0.1x are older than 10 but younger than 12.   (3)\r\n" );
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document.write( "Their sum (1) + (2) + (3) is 0.5x + 0.05x + 0.1x = 0.65x.\r\n" );
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document.write( "The remaining are x - 0.65x = 0.35x,  and the equation is\r\n" );
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document.write( "0.35x = 70.\r\n" );
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document.write( "Then x = \"70%2F0.35\" = 200.\r\n" );
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document.write( "Thus there are 200 students in the school.\r\n" );
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document.write( "Hence, 10-years old student's population is 0.1*200 = 20.\r\n" );
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