Answer :
Final answer:
To find the stock owned by neither Rob nor Talia, calculate Talia's ownership as half of Rob's, determine their combined ownership, and subtract it from the whole.
Explanation:
To determine the part of the stock that is owned by neither Rob nor Talia, first find out how much stock Talia owns. Since Talia owns half as much stock as Rob, she owns 5/9 * 1/2 = 5/18 of the stock. The combined ownership of Rob and Talia is 5/9 + 5/18 = 15/18 of the stock. To find the part of the stock owned by neither Rob nor Talia, subtract their combined ownership from the whole stock: 1 - 15/18 = 3/18 = 1/6.