99. Solving a chemistry problem

1. When a non-competitive inhibitor is added to the enzymatic system following the Michaelis-Menten scheme (Km=3.0*10-3 mol*l-1), the reaction rate decreased by 70%. The substrate concentration is 2.5*10-3 mol*l-1, the inhibitor concentration is 5.0*10-4 mol*l-1. At what inhibitor concentration will the reaction rate be 35% of the initial one?