If half of the people in Nantucket are going to the planned meeting, then there are 1/2*300 = <<300*1/2=150>>150 people going to the meeting.
If the number of males going to the meeting is twice the number of females, we'll assume the number of females is x and the number of males is 2x.
We know that x+2x=150
Adding like terms produces 3x=150
After dividing both sides by 3, we have x = 150/3 = <<150/3=50>>50
The number of females attending the meeting is x = <<50=50>>50
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