3. In a semiconductor company three machines, A, B, and C,
fabricate integrated circuits (ICs). Machine A produces 20% of the
ICs, machine B produces 30% of the ICs, and machine C produces 50%
of the ICs. The ICs are assumed to be identical. It is known that 3
in every 1000 ICs made by machine A are defective, 1 in every 125
ICs made by machine B is defective, and 1 in every 250 ICs made by
machine C...