$($d$)$ If there is material for producing $20$ million Band$-$Aids on average in the process and throughput is on average $800,000$ band$-$aids per hour, how long does it take to produce on average a Band$-$Aid from start to finish in hours? $($Note: It's hard to believe, but $4$ billion band$-$aids per year are actually produced at some facilities.$)$

$2$

$($e$)$ Given the information above: if material has to wait on average $45$ minutes in WIP waiting for the assembler machine, how many band$-$aids can be made out of that material?