A rectangular metal sheet is of length 24 cm and breadth 18 cm. From each of its corners a square of side x cm is cut off and an open box is made of the remaining sheet. If the volume of the box is 640 cubic cm, then what is the value of x?

  1. A. 2
  2. B. 3
  3. C. 4
  4. D. 6

Correct Answer: C. 4

Explanation

The dimensions of the open box formed will be (24-2x), (18-2x), and x. Its volume is x(24-2x)(18-2x) = 640. Checking the given options: if x=4, the volume is 4(24-8)(18-8) = 4 \times 16 \times 10 = 640, which satisfies the equation.

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