Question #$1$:

The time to assemble the first unit on a production line is $10$ hours. The learning rate is $0\mathrm{.}90.$ Approximately how long will it take for the sixth unit to be assembled?

A$.50\mathrm{.}2$ hours

B$.0\mathrm{.}026$ hours

C$.7\mathrm{.}6$ hours

D$.12$ hours