A uniform path is constructed all around the outside of a rectangular bed that is 18 metres long and 12 metres wide. The total area of the bed and the path is 352 square metres. What is the width of the path?
Answer and explanation
Correct answer: 2 m
Let the width of the path be \(x\) metres. The outer rectangle then has length \(18+2x\) and breadth \(12+2x\). Hence, \((18+2x)(12+2x)=352\), which gives \(x^2+15x-34=0\). Factoring, \((x-2)(x+17)=0\), so \(x=2\) or \(x=-17\). A width cannot be negative, so \(x=2\) metres. Exam tip: Since the path is added on both sides of each dimension, use \(18+2x\) and \(12+2x\), not \(18+x\) and \(12+x\).
Frequently asked questions
What is the correct answer to this question?
2 m
Why is this the correct answer?
Let the width of the path be \(x\) metres. The outer rectangle then has length \(18+2x\) and breadth \(12+2x\). Hence, \((18+2x)(12+2x)=352\), which gives \(x^2+15x-34=0\). Factoring, \((x-2)(x+17)=0\), so \(x=2\) or \(x=-17\). A width cannot be negative, so \(x=2\) metres. Exam tip: Since the path is added on both sides of each dimension, use \(18+2x\) and \(12+2x\), not \(18+x\) and \(12+x\).
Which subject and chapter does this question cover?
This is a Class 10 Mathematics question. Chapter: Quadratic Equations. Topic: Word Problems and Applications.
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