Question

Area of square field is 8 hectares. How long would a man take to cross it diagonally by walking at the rate of 4 km per hour

Answer 1

$area = {side}^{2} \\ 8 = {side }^{2} \\ side = \sqrt{8} \\ side = 2 \sqrt{2}$
$diagonal = \sqrt{ {side}^{2} + {side}^{2} } \\ d = side \sqrt{2} \\ d = 2 \sqrt{2} \times \sqrt{2} \\ d = 2 \times 2 \\ d = 4$
$rate = \frac{4}{4} \\ rate = 1 \: hour$