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

_________________

Brent Hanneson – Creator of greenlighttestprep.com

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