1a.) In a project activity network, activity F has three immediate predecessors: B, C, and E. The earliest completion times for B, C, and E are 6, 18, and 11 days. What is the earliest start time for F?

1b.) A firm made 90,315 units in 2009, with an average of 90 employees.In 2010, the production was 110,348 units, with an average of 96 employees.What is the percentage increase in productivity from 2009 to 2010?(Note: if there is a decrease, the increase is negative;provide two digits to the right of the decimal point)