Sun=0, Mon=1,....

$\displaystyle 2+129\equiv x \ \mbox{(mod 7)}\rightarrow 131\equiv x \ \mbox{(mod 7)}$

Here is what I did, and I obtained the correct answer; however, I think this should have been done another way.

$\displaystyle 131-\left \lfloor \frac{131}{7} \right \rfloor*7=5$

$\displaystyle 131\equiv 5 \ \mbox{(mod 7)}$

In 129 days, it will be Friday.