If there are 12 campers and 6 canoes in total, but only 4 of them are good (since 2 are leaking), we need to divide the 12 campers among the 4 good canoes.
To find out how many campers will ride in each good canoe, we can perform the following calculation:
\[ \text{Number of campers in each good canoe} = \frac{\text{Total campers}}{\text{Number of good canoes}} = \frac{12}{4} = 3 \]
So, each good canoe will hold 3 campers.