• # question_answer The area of a square field is 24200 sq m. How long will a lady take to cross the field diagonally at the rate of 6.6 km/h? A)  3 min   B)  2 min C)  2.4 min D)  2 min 40 s

Let ?a? m be the length of a side of the square field. Therefore, its area =${{a}^{2}}$sq m               ?(i) the length of the diagonal ?d? of a square whose side is ?a? m $=a\sqrt{2}$ From Eqs. (i) and (ii), we can deduce that the square of the diagonal $={{d}^{2}}=2{{a}^{2}}$ $\Rightarrow$   $d=\sqrt{(2}\times \,\,Area)$ $=\sqrt{2\times 24200}$ $=\sqrt{48400}=220\,\,m$ The time taken to cross a length of 220 m while travelling at 6.6 km/h is given by 220 m/6.6 km/h$=\frac{(220\times 60)}{(6.6\times 1000)}$(converting 1km = 1000 m and 1 h = 60 min) = 2min