document.write( "Question 1164747: Robert is thinking that his father is 7 years older than twice his age, his grandfather is 4 years less than twice his father’s age. If Robert’s grandfather is 70 years old, how old is Robert ? \n" ); document.write( "
Algebra.Com's Answer #789158 by ankor@dixie-net.com(22740)\"\" \"About 
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Robert is thinking that his father is 7 years older than twice his age,
\n" ); document.write( "f = 2r + 7
\n" ); document.write( "his grandfather is 4 years less than twice his father’s age.
\n" ); document.write( "g = 2f - 4
\n" ); document.write( "If Robert’s grandfather is 70 years old,
\n" ); document.write( "g = 70
\n" ); document.write( ":
\n" ); document.write( "Replace g with 70 in the 2nd equation
\n" ); document.write( "2f - 4 = 70
\n" ); document.write( "2f = 70 + 4
\n" ); document.write( "2f = 74
\n" ); document.write( "f = 74/2
\n" ); document.write( "f = 37
\n" ); document.write( ":
\n" ); document.write( "how old is Robert ?
\n" ); document.write( "in the first equation, replace f with 37
\n" ); document.write( "2r + 7 = 37
\n" ); document.write( "2r = 37 - 7
\n" ); document.write( "2r = 30
\n" ); document.write( "r = 30/2
\n" ); document.write( "r = 15 yrs is Robert's age
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