Step-by-step explanation:
The probability of selecting no bad ones is the probability of
selecting 2 from the 8 good bulbs, which is C(8,2)/C(10,2) or it can also be written as (8C2)/(10C2) = 28/45
The probability of selecting 1 good one and one bad one, is the
probability of selecting 1 from the 8 good bulbs, and one from
the 2 bad ones, which is [C(8,1)C(2,1)]/C(10,2) or as some people
write it (8C1×2C1)/(10C2) = 16/45.
The probability of selecting two bad one, is C(2,2)/C(10,2) or
as some people write it (2C2)/(10C2) = 1/45.
