Understanding and using the Henri-Michaelis-Menten equation.

For an enzyme which obeys Henri-Michaelis-Menten kinetics,
(1) At what substrate concentration will an enzyme characterized by a kcat of 30 s-1 and Km of 0.005 M show one quarter of its maximal rate?

(2) Calculate the fraction of Vmax that would be found when [S]=0.5 Km, [S]=3Km, and [S]=10Km