Between 2:30 pm and 5:00 pm, there are 2.5 hours.
There are 60 minutes in an hour, so 2.5 hours x 60 = <<2.5*60=150>>150 minutes.
Her family was in the bathroom 45 + 30 + 20 = <<45+30+20=95>>95 minutes.
Mrs. Parker has 150 minutes – 95 minutes = <<150-95=55>>55 minutes in the bathroom.
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