Work Rate Problems
Express each worker's rate as "fraction of job per hour," then add rates for combined work.
- A finishes in 4 hours → rate = 1/4 job/hr
- B finishes in 6 hours → rate = 1/6 job/hr
- Together: 1/4 + 1/6 = 3/12 + 2/12 = 5/12 job/hr
- Time together = 1 ÷ (5/12) = 12/5 = 2.4 hours
If one entity fills (adds) and another drains (removes), subtract their rates.