Question 3
Teams $A$ and $B$ each have 10 workers. Team $A$ can build a road in 14 days and a bridge in 25 days. Team $B$ can build the same road in 18 days and the same bridge in 15 days. Team $C$ consists of five workers from $A$ and five from $B$. It builds the road first and then the bridge. How many days does it need altogether?
Model clarification: for each job, all workers within an original team have equal, constant productivity, and their work rates add. Productivity may differ between the two teams and between the two jobs.
Model clarification: for each job, all workers within an original team have equal, constant productivity, and their work rates add. Productivity may differ between the two teams and between the two jobs.