A factory has a total of three manufacturing units, $ M_1, M_2, M_3 $, which produce bulbs independently of each other. The units $ M_1, M_2, M_3 $ produce bulbs in the proportions $ 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 $ M_1 $, 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 $ M_2 $ is $ \frac{2}{5} $.
If a bulb is chosen randomly from the bulbs produced by $ M_3 $, then the probability that it is defective is ________.