ABC26GN4341 · Area

Subject: General Aptitude · Chapter: Area · Exam: 2009 · Marks: · Difficulty:

The length of a rectangular blackboard is 8 m more than its breadth. If its length is increased by 7m and its breath is decreased by 4 m, its area remains unchanged. The length and breadth of the rectangular blackboard is

(a)24 m, 16 m

(b)20 m, 24 m

(c)28 m, 16 m

(d)28 m, 20 m

Answer

Answer (as printed): D

Explanation

Let breadth $=x \mathrm{cm}$. Then, length $=(x+8) \mathrm{m}$. $$\begin{aligned} & \therefore(x+8) x=(x+15)(x-4) \\ & \Leftrightarrow x^{2}+8 x=x^{2}+11 x-60 \\ & \Leftrightarrow x=20 . \end{aligned}$$ So, length $=28 \mathrm{m}$ and breadth $=20 \mathrm{m}$.

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