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Question
Length of a rectangle is three times its breadth. Perimeter of the rectangle is 40 cm. Find its length and width.
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Solution
Let l and b are length and breadth respectively of the given rectangle.
According to question, l = 3b
Perimeter of the rectangle = 2(1 + b)
⇒ 40 cm = 2(3b + b)
⇒ 40 cm = 2 × 4b
⇒ 40 cm = 8b
⇒ `40/8` cm = b
⇒ b = 5 cm
∴ The required length = 3 × 5 cm = 15 cm and breadth = 5 cm
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