A firm has redesigned its production process $-$ it now takes $10$ hours for a unit to be made $($flow time or throughput time$),$ whereas earlier it took $15$ hours.

If the process completes one unit per hour on average $($this is cycle time, the same now and earlier$),$ and each unit is worth $$4,500($on average throughout the production line$),$ what is the reduction in work$-$in$-$process value $($in dollars$)?($Note: reduction in dollars, not as a percentage.$)$