document.write( "Question 631067: Five years ago Jacob was one-sixth the age of his brother. Three years time his age doubled will match his brother's age. How old is Jacob now? \r
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Algebra.Com's Answer #397324 by htmentor(1343)\"\" \"About 
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Let J = Jacob's age now
\n" ); document.write( "Let B = his brother's age now
\n" ); document.write( "5 years ago Jacob was 1/6 his brother's age:
\n" ); document.write( "J-5 = (B-5)/6
\n" ); document.write( "In 3 years, his age doubled will equal his brother's age:
\n" ); document.write( "2*(J+3) = B+3
\n" ); document.write( "We have two equations and two unknowns
\n" ); document.write( "Use one of the equations to solve for B in terms of J:
\n" ); document.write( "2J + 6 = B + 3
\n" ); document.write( "B = 2J + 3
\n" ); document.write( "J-5 = ((2J+3)-5)/6
\n" ); document.write( "J-5 = (2J-2)/6
\n" ); document.write( "6J-30 = 2J-2
\n" ); document.write( "This gives J = 7
\n" ); document.write( "So Jacob's age is 7
\n" ); document.write( "Check:
\n" ); document.write( "His brother's age = B = 2*7 + 3 = 17
\n" ); document.write( "5 years ago Jacob was 2, his brother was 12 (=6 times his age)
\n" ); document.write( "3 years from now Jacob will be 10
\n" ); document.write( "2*10 = 20 = 17 + 3 \n" ); document.write( "
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