document.write( "Question 935712: The average age of 30 boys in a class is 15 years. One boy aged 20 years, left the class, but two new boys came in his place whose age differ by 5 years. If the average age of all the boys now in the class remains 15 years, the age of the youngest new comer is? \n" ); document.write( "
Algebra.Com's Answer #568999 by Theo(13342)\"\" \"About 
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the average age of the boys is 15.
\n" ); document.write( "the number of boys is equal to 30
\n" ); document.write( "the total age of the boys is equal to 15*30 = 450
\n" ); document.write( "one boy aged 20 leaves the group.
\n" ); document.write( "2 other boys join the group.
\n" ); document.write( "the boys differ in age by 5 years.
\n" ); document.write( "let x equal the age of one of the boys.
\n" ); document.write( "let x + 5 equal the age of the other of the boys.
\n" ); document.write( "there were 30 boys to start with.
\n" ); document.write( "now there are 31 (30 - 1 + 2 = 31).
\n" ); document.write( "the average age of the boys is still 15.
\n" ); document.write( "you get:
\n" ); document.write( "(450 - 20 + x + x + 5) / 31 = 15
\n" ); document.write( "simplify by combining like terms to get:
\n" ); document.write( "(450 - 15 + 2x) / 31 = 15
\n" ); document.write( "multiply both sides of this equation by 31, and simplify further by combining the constants together, to get:
\n" ); document.write( "435 + 2x = 465
\n" ); document.write( "subtract 435 from both sides of the equation to get:
\n" ); document.write( "2x = 30
\n" ); document.write( "divide both sides of the equation by 2 to get:
\n" ); document.write( "x = 15
\n" ); document.write( "the boys that are added are aged 15 and 20.
\n" ); document.write( "the age of the youngest is 15.
\n" ); document.write( "that's your solution.\r
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