Of every 10000 resistors, 36%, i.e.  = 3600 are made by the machine A, and every 5% of these 3600, i.e.  = 180 are defective.


Of every 10000 resistors, the rest 64%, i.e.  = 6400 are made by the machine B, and every 2% of these 6400, i.e.  = 128 are defective.


Given that a resistor chosen at random is defective means that you choose it from 180+128 = 308 defective.


It is your space of events under the given restriction.


Then the conditional probability under the question is   = 0.584 = 58.4%.