$3.$ The speed at which you can log into a website through a smartphone is an important quality characteristic of that website. In a recent test, the mean time to log into the Hertz website through a smartphone was $7\mathrm{.}5$ seconds. Suppose that the download time is normally distributed, with a standard deviation of $1\mathrm{.}7$ seconds. What is the probability that a download time is

a$.$ less than $7$ seconds?

b$.$ between $7\mathrm{.}5$ and $8\mathrm{.}5$ seconds?

c$.$ above $8\mathrm{.}1$ seconds?

d$.$ Ninety$-$nine percent of the download times are slower $($higher$)$ than how many seconds?

e$.$ Ninety$-$five percent of the download times are between what two values, symmetrically distributed around the mean?