Verified Solution Mathematics Quadratic Equations

A piece of cloth costs Rs 30. If the piece were 1 m longer and each metre costs Re 1 less, the cost would remain unchanged. What is the length of the piece?

9 views 3 helpful Updated Jul 14, 2026
Solution ✔ Verified
  • A5 m
  • B6 m
  • C7 m
  • D8 m
Explanation

Let the original length of the cloth be x metres. The original cost per metre is 30/x. If the length were x+1 metres, the new cost per metre would be 30/(x+1). The problem states that the new cost per metre is Re 1 less than the original, so (30/x) - (30/(x+1)) = 1. This simplifies to 30(x+1) - 30x = x(x+1) => 30 = x² + x => x² + x - 30 = 0. Factoring gives (x+6)(x-5) = 0. Since length cannot be negative, x = 5 metres.

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