After mixing, which species has the dominant affect on the pH of the solution that remains? A solution is created by mixing $250\,\mathrm{mL}$ of $1\,\mathrm{M}$ $\ce{HCl}$, $250\,\mathrm{mL}$ of $1\,\mathrm{M}$ $\ce{CH3COOH}$ and $500\,\mathrm{mL}$ of $1.5\,\mathrm{M}$ $\ce{CsOH}$.

The $K_\mathrm{a}(\ce{CH3COOH}) = 1.8 \times 10^{-5}$

What is the $\mathrm{pH}$ of this solution?

I am stuck between $\ce{HCl}$ and $\ce{CsOH}$ since they are both a strong acid and base (respectively) meaning that they should both have a substantial affect on the $\mathrm{pH}$. 

Also when determining what the $\mathrm{pH}$ is, which species would we use in our ICE table?
CsOH is a strong base.

0.5 L X 1.5 M = 0.75 moles of hydroxide.  

Similarly, there are 0.5 moles of monoprotic acid.  

After mixing there will be 0.25 moles of hydroxide in 1 liter of solution. 

In other words [OH-] = 0.25M

pH is approximately 14 + log (0.25) = 13.4