document.write( "Question 766858: Eight students of average 13 years leave a class of 30 students of average age 15 years. If seven new students of average 12 years join the class, find the present average age of the students in the class \n" ); document.write( "

Algebra.Com's Answer #467318 by ramkikk66(644) $\"\"$ $\"About$

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document.write( "Question:\r\n" );
document.write( "Eight students of average 13 years leave a class of 30 students of average age 15 years. If seven new students of average 12 years join the class, find the present average age of the students in the class\r\n" );
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document.write( "Answer:\r\n" );
document.write( "Remember that, at all times: \r\n" );
document.write( "Average age of n students = total age of n students / n\r\n" );
document.write( "Similarly, if the average age is x, for n students, total age = average * number\r\n" );
document.write( "of students = n*x\r\n" );
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document.write( "Using these, we can solve the problem.\r\n" );
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document.write( "Initially the class has 30 students of average age 15.\r\n" );
document.write( "Total age of 30 students = 30*15 = 450\r\n" );
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document.write( "8 students of average age 13 leave the class.\r\n" );
document.write( "Total age of students who left = 8*13 = 104\r\n" );
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document.write( "Number of students left = 30 - 8 = 22\r\n" );
document.write( "Total of the students left = 450 - 104 = 346\r\n" );
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document.write( "Now, 7 students of average age 12 are added.\r\n" );
document.write( "Total age of new students = 7*12 = 84\r\n" );
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document.write( "Finally, number of students = 22 + 7 = 29\r\n" );
document.write( "Total age of the 29 students = total age of the 22 old students + total age\r\n" );
document.write( "of the 7 new students = 346 + 84 = 430\r\n" );
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document.write( "So the present average = \r\n" );
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document.write( "Hope you got it :)\r\n" );
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