To construct a circuit a student needs, among others, 12 chips of a certain type. The student knows that 4% of these chips are defective. How many chips have to be provided so that, with a probability...

To construct a circuit a student needs, among others, 12 chips of a certain type. The student knows that 4% of these chips are defective. How many chips have to be provided so that, with a probability of not less than 0.9, the student has a sufficient number of nondefective chips in order to be able to construct the circuit?