A typist uses a paper 30 cm by 15 cm. He leaves a margin of 2.5 cm at the top and bottom and 1.25 cm on either side. What percentage of paper area is approximately available for typing ?

Answer: Option C

Area of the sheet = (30 × 15) cm² = 450 cm²
Area used for typing
= [(30 - 5) × (15 - 2.5)] cm²
= 312.5 cm²
∴ Required percentage :
$$\begin{array}{rl}& =\left(\frac{312.5}{450}\times 100\right)\%\\ & =69.4\%\approx 70\%\end{array}$$