A Rectangle’S Length is 5 Cm Less than Twice Its Width. If the Length is Decreased by 5 Cm and Width is Increased by 2 Cm - Mathematics

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Sum

A rectangle’s length is 5 cm less than twice its width. If the length is decreased by 5 cm and width is increased by 2 cm; the perimeter of the resulting rectangle will be 74 cm. Find the length and width of the origi¬nal rectangle.

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Solution

Let width of the original rectangle = x cm

Length of the original rectangle = (2x – 5)cm

Now, new length of the rectangle = 2x – 5 – 5 = (2x – 10) cm

New width of the rectangle = (x + 2) cm

New perimeter = 2[Length+Width] = 2[2x – 10 + x + 2] = 2[3x – 8] = (6x – 16) cm

Given; new perimeter = 74 cm

6x – 16 = 74

⇒ 6x = 74 + 16

⇒ 6x = 90

⇒ x = 15

Length of the original rectangle = 2x – 5 = 2 x 15 – 5 = 30 – 5 = 25 cm

Width of the original rectangle = x = 15 cm

Concept: Solving Linear Inequations
  Is there an error in this question or solution?
Chapter 14: Linear Equations in one Variable - Exercise 14 (B) [Page 169]

APPEARS IN

Selina Concise Mathematics Class 8 ICSE
Chapter 14 Linear Equations in one Variable
Exercise 14 (B) | Q 11 | Page 169
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