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A wire is (7x – 3) metres long. A length of (3x – 4) metres is cut for use. Now, answer the following questions: How much wire is left?

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Question

A wire is (7x – 3) metres long. A length of (3x – 4) metres is cut for use. Now, answer the following questions:

  1. How much wire is left?
  2. If this left out wire is used for making an equilateral triangle. What is the length of each side of the triangle so formed?
Sum
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Solution

Given, length of wire = (7x – 3) m

And wire cut for use has length = (3x – 4) m

a. Left wire = (7x – 3) – (3x – 4)

= 7x – 3 – 3x + 4

= 7x – 3x – 3 + 4

= (4x + 1) m

b. ∴ Left wire = (4x + 1) m

∴ Perimeter of equilateral triangle = Length of wire left

⇒ 3 × (Side) = 4x + 1

⇒ Side = `(4x +1)/3 = 1/3 (4x + 1) m`.

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Chapter 10: Algebraic Expressions - Exercise [Page 325]

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NCERT Exemplar Mathematics Exemplar Class 7
Chapter 10 Algebraic Expressions
Exercise | Q 83. | Page 325

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