Carcass wrote:
Working alone at its constant rate, machine A produces k car parts in 10 minutes. Working alone at its constant rate, machine B produces k car parts in 15 minutes. How many minutes does it take machines A and B, working simultaneously at their respective constant rates, to produce k car parts?
enter your value as minutesAnother approach is to assign a "nice" value to the entire job. That is, a nice value that works well with the two given times (10 minutes and 15 minutes)
Let's say k =
30So, machine A produces
30 car parts in 10 minutes
So, machine A's RATE =
3 parts per minuteAnd machine B produces
30 car parts in 15 minutes
So, machine B's RATE =
2 parts per minuteSo, the COMBINED rate of both machines =
3 +
2 =
5 parts per minuteHow many minutes does it take machines A and B, working simultaneously at their respective constant rates, to produce k (30) car parts?Time = output/rate
=
30/
56 minutes
Answer:
Cheers,
Brent
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Brent Hanneson – Creator of greenlighttestprep.comSign up for GRE Question of the Day emails