$1.(25$ points$)$ Find the lowest unit cost of a dozer$-$scraper fleet given the following information:

Scraper load time is $1$ minute, haul and return times are $7$ and $5$ minutes respectively; dump

and turn times total $3$ minutes; Scraper heaped capacity is $35$ LCY$.$

Scraper cost is $$300/$hr; Dozer cost is $$250/$hr$.$

HINTS:

$-$ Find pusher cycle time $($Formula in scrapers PPT$)$ and scraper cycle times from data

given.

$-$ Calculate Balance Number.

$-$ Calculate productivity and Unit Cost for integer above and below balanced number.

Select lowest cost.