First find the total amount of water Violet and her dog consume per hour: 800 ml + 400 ml = <<800+400=1200>>1200 ml
Then divide that amount by 1000 ml/L to convert it to liters: 1200 ml / 1000 ml/L = <<1200/1000=1.2>>1.2 L
Then divide Violet's carrying capacity by the amount of water they drink per hour to find how many hours she can hike: 4.8 L / 1.2 L/hour = 4 hours
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