Maths · Distance formula, sections formula, locus and its equation

A company makes a metallic block having square bases with volume 640 and height

A company makes a metallic block having square bases with volume 640 \( c m^{3}, \) and height \( 10 \mathrm{cm} . \) If Robin wants to paint the block with the paints at the rate of Rs 15 per \( c m^{2} \), then find the cost of painting Robin has to pay.

  • A. Rs 5680
  • B. Rs 6595
  • C. Rs 6720
  • D. Rs 6690

Step-by-step solution

Volume = base area × height => base area = 640/10 = 64 cm². Side of square base = √64 = 8 cm. Total surface area = 2(8×8) + 4(8×10) = 128 + 320 = 448 cm². Cost = 448 × 15 = Rs 6720.
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