Daltons law problems?

Daltons Law states that partial pressure (pp) of an ideal gas is the product of mole fraction and total pressure. Since the gas mixture consists of 1 mole of hydrogen and 3 moles of helium, then the total mole = 1 + 3 = 4 moles. The mole fraction of hydrogen then = 1/4 = 0.25. Therefore the pp of hydrogen = 0.25 x 40 = 10 kPa