Brittney and Bradley are going on a canoeing trip down the Red River. They canoe to elk island, stop for lunch for one hour, and then return home. The current is flowing at 6.0 mi/h downstream and they paddle a total of distance of 21 miles. Their total trip time was 6.3 hours, including their 1-hour break for lunch. How long does it take them to reach Elk Island on the first half of their trip?

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