Problema Solution

One crew can seal a parking lot in 9 hours and another in 12 hours. How long will it take to seal the parking lot if the two crews work together?

Answer provided by our tutors

The rate of the first crew is: 1/9 parking per hour

The rate of the second crew is: 1/12 parking per hour

Let 'x' represent the hours spent on completing the job if the crews worked together.

1/x parking per hour is the together rate.

Now we can write the following equation:

1/9 + 1/12 = 1/x

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click here to see the equation solved for x

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x = 36/7 hr

x = 5 hr (1/7)*60 min

x = 5 hr 8.6 min

If the 2 crews worked together then they will seal the parking lot is 5 hours and 8.6 minutes.