Area of bottom of the box is (A) = 58.8 cm^2 = 58.8x10^-4 m^2 , Mass of the box (M)= 12 kg , Acceleration due to gravity (g) = 9.8 m/s^2 ... Formula for Pressure is = Force/Area. Therefore Pressure exerted by the box= 12 x 9.8 / 58.8 x 10^-4 = 2x 10^4 N/m^2..