document.write( "Question 714908: Frank is 17 years old and his grandfather is 77 years old. How old will Frank's grandfather be when he is exactly 4 times as old as Frank? \n" ); document.write( "

Algebra.Com's Answer #439044 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Frank is 17 years old and his grandfather is 77 years old.
\n" ); document.write( " How old will Frank's grandfather be when he is exactly 4 times as old as Frank?
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\n" ); document.write( "Let y = the number years later for this to be true
\n" ); document.write( "77 + y = 4(17 + y)
\n" ); document.write( "77 + y = 68 + 4y
\n" ); document.write( "77 - 68 = 4y - y
\n" ); document.write( "9 = 3y
\n" ); document.write( "y = 9/3
\n" ); document.write( "y = 3 yrs, when Grandpa will 4 times as old as Frank
\n" ); document.write( ":
\n" ); document.write( "At that time (add 3 to their ages), Grandpa will 80, and Frank will be 20 \n" ); document.write( "

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