document.write( "Question 511673: spongebob is 3 years older than his sister spongebabe. In 7 years, she will be six-sevenths his age. How old are they? \n" ); document.write( "
Algebra.Com's Answer #342351 by Maths68(1474)\"\" \"About 
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Let
\n" ); document.write( "Present age of spongebob = r
\n" ); document.write( "Present age of spongebabe = m
\n" ); document.write( "spongebob is three years older than his sister spongebabe means if we add 3 years to present age of spongebabe both spongebob and spongebabe will be of equal age
\n" ); document.write( "r=m+3...........(1)
\n" ); document.write( "In 7 years means we have add 7 in their present age
\n" ); document.write( "r+7=m+7
\n" ); document.write( "then she will be six-sevenths of his age
\n" ); document.write( "6/7(r+7)=(m+7)
\n" ); document.write( "6(r+7)=7(m+7)
\n" ); document.write( "6r+42=7m+49
\n" ); document.write( "6r=7m+49-42
\n" ); document.write( "6r-7m=7
\n" ); document.write( "Put the value of r from (1) to above equation
\n" ); document.write( "6(m+3)-7m=7
\n" ); document.write( "6m+18-7m=7
\n" ); document.write( "-m=7-18
\n" ); document.write( "-m=-11
\n" ); document.write( "Multiply by (-1) both sides
\n" ); document.write( "m=11
\n" ); document.write( "Put the valuel of m in (1)
\n" ); document.write( "r=m+3...........(1)
\n" ); document.write( "r=11+3
\n" ); document.write( "r=14
\n" ); document.write( "Present age of spongebob = r = 14
\n" ); document.write( "Present age of spongebabe = m = 11\r
\n" ); document.write( "\n" ); document.write( "Check
\n" ); document.write( "In 7 years spongebabe will be 6/7 of spongebob
\n" ); document.write( "spongebabe=11+7=18
\n" ); document.write( "spongebob=14+7=21
\n" ); document.write( "spongebabe=6/7(spongebob)
\n" ); document.write( "spongebabe=6/7(21)
\n" ); document.write( "spongebabe=6(3)
\n" ); document.write( "spongebabe=18 \n" ); document.write( "
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