First find the total number of cups of juice: 6 quarts * 4 cups/quart = <<6*4=24>>24 cups
Then find the reduced volume of the juice: 24 cups * 1/12 = <<24*1/12=2>>2 cups
Then add the volume of the sugar to find the total volume of the syrup: 2 cups + 1 cups = <<2+1=3>>3 cups
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