Zia Homes is contracted to frame $32$ wooden houses of the same design in a new subdivision of $300$ homes. The fourth unit took $420$ hours, but the company expects to cut about $10\%$ off the time for each replication of the same design. Use the learning curve assumption of a constant decrease with each doubling of production to estimate past completion times $($units $1$ and $2)$ and the completion time for units $8$ and $32.$ Round to the nearest hour.

The completion time for unit $1$ was

hours.

The completion time for unit $2$ was

hours.

The completion time for unit $8$ is

hours.

The completion time for unit $32$ is

hours.