The formula to calculate osmotic pressure is
Osmotic Pressure = M R T
M = Molarity
R = Ideal Gas Constant
T = Temperature in Kelvin
So,
24.6/.2254kg=109.139g /kg >>>>> Molarity
109.139 x mols/92 g = 1.186 mols kg^-1
1.186 x 0.08134 x 298 K = 28.755 atm
1.06852 x 0.08134 x 298K= 26.5 atm
The answer is 26.5