CA Foundation · Quantitative Aptitude · Equations
The length of a rectangular plot is 5 metres more than its breadth, and its area is 336 square metres. What is the perimeter of the plot?
Taking the breadth as x metres, the length is x + 5, so x² + 5x − 336 = 0. This gives x = 16 after rejecting the negative root, and the length is 21. The perimeter is 2 × 37 = 74 metres.
- A32 m
- B42 m
- C37 m
- D74 mCorrect
Explanation
Let the breadth be x, so x(x + 5) = 336, i.e. x² + 5x − 336 = 0. This factorises as (x + 21)(x − 16) = 0, and the negative root is rejected, so breadth = 16 m and length = 21 m. Perimeter = 2(16 + 21) = 74 m. The value 37 is only the semi-perimeter.
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