help asap please Problem $15-315-3.$ The following system consists of components with the indicated nonfailure probabilities: Use the reliability values of A to F given in Problem $15-8,$ and shown below. $15-21$ For the data provided in Problem $15-3,$ determine $($a$)$ minimum length of crest vertical

curves, $($b$)$ minimum length of sag vertical curves, using the rate of vertical curvature

method when joining two segments at maximum grade, $($c$)$ maximum superelevation,

and $($d$)$ maximum degree of curve $($use $f_s=0\mathrm{.}15)($deg$-$min$-$sec$).$

$15-13$ Given a simple circular curve with the following properties: $D=11,$ bearing on incoming

$($back$)$ tangent is $N89{27}^{\text{'}}{25}^{\text{'}\text{'}}E,$ bearing on outgoing $($forward$)$ tangent is $S6010{05}^{\text{'}\text{'}}E,$

the station of the $\frac{?}{PI}=22+69\mathrm{.}77.$

$[$ R$($A$)=0\mathrm{.}99$; R$($B$)=0\mathrm{.}95$; R$($C$)=0\mathrm{.}85$; R$($D$)=0\mathrm{.}90$; R$($E$)=0\mathrm{.}85$; R$($F$)=0\mathrm{.}99]$