A factory has a total of three manufacturing units, M₁, M₂, and M₃, which produce bulbs independent of each other. The units M₁, M₂, and M₃ produce bulbs in the proportions of 2 : 2 : 1, respectively. It is known that 20% of the bulbs produced in the factory are defective. It is also known that, of all the bulbs produced by M₁, 15% are defective. Suppose that, if a randomly chosen bulb produced in the factory is found to be defective, the probability that it was produced by M₂ is 2/5. If a bulb is chosen randomly from the bulbs produced by M₃, then the probability that it is defective is _______________.