What is the work rate (combined job) problem?
This is the classic "work problem" from arithmetic: two teams can each finish the same job alone in a known number of days, and you want to know how fast they finish if they work together. It applies universally to any job that two workers, machines, or pipes share — painting a wall, filling a tank, or completing a project.
How to use it
Enter Team A's required days (how long Team A needs alone) and Team B's required days (how long Team B needs alone) using the same time unit. The calculator returns each team's per-day work rate, the combined rate, and the number of days needed when both work together. If you measure in hours instead of days, the answer comes out in hours — just keep both inputs in the same unit.
The formula explained
Treat the whole job as 1 unit of work. Team A completes a fraction 1/a of the job per day, and Team B completes 1/b per day. When they work side by side their rates add, giving a combined rate of
Worked example
Suppose Team A needs 16 days and Team B needs 10 days. Team A's rate is 1/16 = 0.0625 job/day and Team B's is 1/10 = 0.1 job/day. The combined rate is 0.1625 job/day, so together they finish in
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