Dalton's Law or Law of Partial Pressures says that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas that composes it. The partial pressure of a gas on the other hand is defined as the pressure it would exert if it were alone in the container.
So we need to sum all the values:
64 + 50.8 = 114.8 kPa
Answer: 114.8 kPa
