Answer:
probability at least one zero is 0.3439
Step-by-step explanation:
given data
last four digits = randomly selected
to find out
probability that for one such phone number the last four digits include at least one 0.
solution
we know there are total 10 digit
so we first find probability of non zero digit i.e.
Probability ( non zero ) = 9 /10 = 0.9
and now we find probability of none of digit zero only event happen n= 4 time in a row by multiplication rules i.e
Probability ( none zero in 4 digit ) =
Probability ( none zero in 4 digit ) =
Probability ( none zero in 4 digit ) = 0.6561
so we can say probability at least one zero = 1 - Probability ( none zero in 4 digit )
probability at least one zero = 1 - 0.6561
probability at least one zero is 0.3439