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An artist has 50 inches of oak trim to frame a painting.
The frame is to have a border 3 inches wide surrounding the painting.
(a) If the painting is square, what are its dimensions?
What are the dimensions of the frame?
(b) If the painting is rectangular with a length twice its width, what are
the dimensions of the painting? What are the dimensions of the frame?
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(a) Imagine this painting surrounded by 3 inches wide frame.
Let x be size of the painting square, in inches.
Then from the problem, you have this equation for x
(x+3) + (x+3) + (x+3) + (x+3) = 50 inches,
or
4(x+3) = 50.
It gives
x+3 = 50/4 = 12.5 inches,
x = 12.5 - 3 = 9.5 inches.
Thus the dimensions of the painting are 9.5 by 9.5 inches. <<<---=== Answer to (a).
Outer dimensions of the frame are 9.5 + 3 + 3 = 15.5 inches. <<<---=== Answer to (a).
(b) Let w be the width of the painting, in inches.
Then the length of the painting is 2x inches.
From the problem, you have this equation for x
(2w+3) + (w+3) + (2w+3) + (w+3) = 50 inches,
or
6w+12 = 50.
It gives
w = (50-12)/6 = 38/6 = 6 inches (the width),
2x= 12 inches (the length).
Thus the dimensions of the painting are 6 inches by 12 inches. <<<---=== Answer to (b).
Outer dimensions of the frame are 6 + 3 + 3 = 12 and 12 + 3 + 3 = 18 inches. <<<---=== Answer to (b).
Solved in full.
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Be aware: both the solution method and the answers in the post by @mananth are incorrect.
They are incorrect, because his setup equations are incorrect, in both cases.