SOLUTION: Please help me solve this word problem step-by-step. (((The Perimeter of the rectangular is 320ft if the length is 5ft longer than twice the width. Find its length and width.)))

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Question 147101: Please help me solve this word problem step-by-step.
(((The Perimeter of the rectangular is 320ft if the length is 5ft longer than twice the width. Find its length and width.)))
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
THe perimeter of a rectangle using length and width is given by,
P=2%2AL%2B2%2AW
For your case, the length is 5 ft longer than twice the width.
1.L=5%2B2%2AW
You also know that
2.P=2%2AL%2B2%2AW=320
Solve eq. 1 for 2W and substitute into eq. 2,
1.L=5%2B2%2AW
2%2AW=L-5
Substitute into eq. 2 and solve for L.
2%2AL%2B2%2AW=320
2%2AL%2B%28L-5%29=320
3%2AL-5=320
3%2AL-5%2B5=320%2B5
3%2AL=325
L=325%2F3
L=108.3
From eq. 1,
2%2AW=L-5
2%2AW=108.3-5
2%2AW=103.3
W=51.7
Check your answers.
2L%2B2W=320
2%28108.3%29%2B2%2851.7%29=320
216.6%2B103.4=320
320=320
True.
L=5%2B2W
108.3=5%2B2%2851.7%29
108.3=5%2B103.4
108.3=108.4
True (off because of roundoff error).
Your answers led to true statement.
They are good answers.