Rates: Average Rates And Combined Rates

More challenging rate problems involve multiple rates:

Average Rates:
An average rate problem will contain two separate rates and will ask for their average. On this type of problem, do not take the average of the two separate rates - —this will be a trap answer. Instead, use the Average Rate formula below to answer the question:

Combined Rates or Work:
Some rate problems will provide the productivity rates of two workers, machines, etc., and will ask for their combined productivity. For these types of problems, use the following work formula:

The Work Formula:

• where x represents the rate at which the first worker can complete the job
• where y represents the rate at which the second worker can complete the job