Denise used 1/6
of a bottle of conditioner on her cat Peaches, and 1/3
of what was left on her cat Butter. How much of the bottle of conditioner did she use on Butter?
If Denise used 1/6 of the bottle of conditioner on Peaches, then 1 - 1/6 = 5/6 of the bottle is left.
Denise used 1/3 of what was left on Butter, so she used (1/3)(5/6) = 5/18 of the bottle on Butter. Answer: \boxed{\frac{5}{18}}.
To determine how much of the bottle of conditioner Denise used on Butter, we need to calculate the amount left after using it on Peaches.
Denise used 1/6 of the bottle on Peaches, which means there is 1 - 1/6 = 5/6 of the bottle left.
Now, Denise used 1/3 of what was left on Butter.
So, the amount of conditioner used on Butter is (5/6) * (1/3) = 5/18 of the bottle.
Therefore, Denise used 5/18 of the bottle of conditioner on Butter.