An earthmoving project has available one loader with a $6-$cy heaped capacity bucket and a larger loader with a $7-$cy heaped capacity bucket for filling $45\mathrm{.}9-$cy heaped capacity off$-$road trucks. All equipment operates at $50-$min hours. Loaders produce a bucket fill factor of $90\%,$ and truck fill factor is $100\%.$ Loaders do not $$short load.$$ Loader cycle time is $0\mathrm{.}6$ min for both loaders $($no travel$).$ Truck dump time is $0\mathrm{.}5$ min $($includes maneuvering, dumping, and turning$).$ The loaded trucks climb uphill through the following three sections and return empty downhill through the same sections. Trucks operate at rated loaded and empty weights