SOLUTION: A poster is 25cm taller than it is wide. It is mounted on a piece of cardboard so that there is a 5cm border on all sides. If the area of the border alone is 1350cm^2, what are the

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Question 174170: A poster is 25cm taller than it is wide. It is mounted on a piece of cardboard so that there is a 5cm border on all sides. If the area of the border alone is 1350cm^2, what are the dimensions of the poster?
Answer by Mathtut(3670) About Me  (Show Source):
You can put this solution on YOUR website!
lets call the width x and the length y=x+25 of the poster......the cardboard area minus the poster area would give us the area of the border(which is 1350).
the cardboard area would be (x+5)(x+25+5)=(x+5)(x+30)=x%5E2%2B35x%2B150
the area of the poster is x(x+25)=x%5E2%2B25x
:
so x%5E2%2B35x%2B150-x%5E2-25x=1350=10x=1200
:
highlight%28x=120%29cm in width
:
highlight%28y=120%2B25=145%29cm in length