Solution: The more big boats, the more money you save. 188 divided by 6=3 1+2. However, it is a waste for two people to take a big boat or a small boat, which can be considered as more than 30, so these eight people can take two small boats, which is cheaper than making a big boat and a small boat.

So: The cheapest way to take a boat is 30 big boats +2 small boats.

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