d$.0\mathrm{.}602$

Questions $16$ and $17$ refer to the problem below.

Customers arrive at a convenience store at an average rate of $4$ customers per $10-$minute period.

QUESTION $16$

What is the percentage probability that exactly $6$ customers arrive in a half$-$hour period?

a$.2\mathrm{.}55\%$

b$.3\mathrm{.}71\%$

c$.1\mathrm{.}93\%$

d$.2\mathrm{.}18\%$