Hi All,

This question revolves around rates and average overall rates, so it can be treated the same way that you would treat an Average Speed question. To determine the average output per hour, we need to know the total cogs produced and the total time spent producing those cogs.

For the first part of the order, we know the rate (40 cogs/hour) and the total produced (60 cogs), so we can figure out the amount of time...

Total Cogs = (Production Rate)(Time)

60 cogs = (40 cogs/hr)(T hours)

60/40 = T

1.5 hours = T

For the second part of the order, we have the same types of information to work with (60 cogs/hr and 60 cogs produced)....

Total Cogs = (Production Rate)(Time)

60 cogs = (60 cogs/hr)(T hours)

60/60 = T

1 hour = T

With the TOTAL COGS (60 + 60 = 120 cogs) and the TOTAL TIME (1.5 + 1 = 2.5 hours), we can now calculate the AVERAGE production rate, in cogs per hour, for the assembly line:

Total Cogs = (Production Rate)(Total Time)

120 cogs = (Rate)(2.5 hours)

120/2.5 = Rate

48 cogs/hour = R

Final Answer:

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