Chapter 6, Problem 6PS

Given a normal distribution with $\mu =50$ and $\sigma =4,$ what is the probability that

$\begin{array}{l}\text{a}\text{.}X>43?\\ \text{b}\text{.}X<42?\\ \text{c}\text{.}\text{Five percent of the values are less what}X\text{Value?}\\ \text{d}\text{.}\text{Between}\text{what}\text{two}X\text{Values (symmetrically}\text{distributed}\text{around}\text{the}\text{mean)}\text{are}\text{60}\text{percent}\text{of}\text{the}\text{values}?\end{array}$