If the solubility of o2 at 0.370 atm and 25 °c is 15.3 g/100 g h2o, what is the solubility of o2 at a pressure of 2.40 atm and 25 °c?

According to Henry's law:

C = K P         when,
C is the solubility of a gas at a constant temperature in a particular solvent.
K is the Henry law constant 
p is the pressure of the gas

we have the pressure and the solubility so we will get the K at first:
by substitution:
0.153 = K * 0.37atm 
K= 0.4
∴ C when P = 2.4 atm
∴ C = 0.37 * 2.4 atm = 0.888   = 88.8 g/100g H2O