there are 4 machines and it is known that exactly two of them are faulty.they are tested one by one,in a random order till both the faulty are identified.then the probability that only two tests are needed is................
please reply soon..............
there are 4 machines and it is known that exactly two of them are faulty.they are tested one by one,in a random order till both the faulty are identified.then the probability that only two tests are needed is................
please reply soon..............










