Simplify \((0.3\times 10^{5})\div (0.4\times 10^{7})\)leaving your answer in standard form

  • A \(7.5\times 10^{-4}\)
  • B \(7.5\times 10^{-3}\)
  • C \(7.5\times 10^{-2}\)
  • D \(7.5\times 10^{-1}\)
waec 2007mathematics

The correct answer is B. \(7.5\times 10^{-3}\)

\((0.3\times 10^{5})\div (0.4\times 10^{7})\\

\frac{3}{10}\times 10^{5}\div \frac{4}{10}\times 10^{7}=3\times 10^{4}\div 4\times 10^{6}\\

\frac{3\times 10^{4}}{4\times 10^{7}}=\frac{3}{4}\times 10^{-2}=0.75\times 10^{-2}\\

7.5\times 10^{-3}\)

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