28. Three partners share the ownership of a sailboat on Lake Michigan. One partner owns $7 / 12$ of the boat and the second owns $1 / 6$. How much of the boat does the third partner own?
a. $5 / 12$
b. $1 / 2$
c. $1 / 3$
d. 1/4

Step 1 ：Three partners share the ownership of a sailboat on Lake Michigan. One partner owns \(\frac{7}{12}\) of the boat and the second owns \(\frac{1}{6}\). We need to find out how much of the boat the third partner owns.

Step 2 ：The total ownership of the boat should be 1 (or 100%). If we subtract the ownership of the first and second partner from 1, we should get the ownership of the third partner.

Step 3 ：Let's denote the ownership of the first partner as \(first\_partner\), the second partner as \(second\_partner\), and the third partner as \(third\_partner\).

Step 4 ：\(first\_partner = \frac{7}{12} = 0.5833333333333334\)

Step 5 ：\(second\_partner = \frac{1}{6} = 0.16666666666666666\)

Step 6 ：Subtract the sum of the first and second partner's ownership from 1 to find the third partner's ownership: \(third\_partner = 1 - first\_partner - second\_partner = 0.25\)

Step 7 ：Final Answer: The third partner owns \(\boxed{\frac{1}{4}}\) of the boat.