$($d$)$ Given IP address: $192\mathrm{.}168\mathrm{.}1\mathrm{.}15/26($i$)$ Compute the subnet mask for this IP$.($ii$)$ What are the total hosts? $($iii$)$ How many are valid? $($iv$)$ What is the Broadcast ID$?($v$)$ What are the First and Last Usable IPs?