Girish Shambu and William Reisel are teammates at a discount store: their new job is assembling bicycles for customers. The assembly of a bike has a learning rate of 80%. They forgot to time their effort on the first bike, but spent 6 hours on the second. They have 6 mote bikes to do. Determine approximately how much time will be (was) required for.
a). the first unit =____hours (two decimal points)
b). the 8th unit=____hours( two decimal points)
c). the total amount of hours to build the 8 units=____hours (two decimal points)