Revision Test 16 555
operating conditions and the remainder give too low
a gain.
Calculate the probability that when drawing two
transistors in turn, at random, with replacement,
of having
(a) two satisfactory,
(b) none with low gain,
(c) one with high gain and one satisfactory,
(d) one with low gain and none satisfactory.
Determine the probabilities in (a), (b) and (c)
above if the transistors are drawn without
replacement.
(14)