Answer :
[tex]x+y+z=47\\y=3x\\z=5x+2\\\\x+(3x)+(5x+2)=47\\9x=45\\x=5\\\\y=3(5)\\y=15\\\\z=5(5)+2\\z=25+2\\z=27[/tex]
The third piece is the longest at 27 feet.
The third piece is the longest at 27 feet.