(3×197-2×1)×0.4×1

————————————×1.5=

3×197

0.5979695431 and rounded 0.6%

So according to my calculations there is a 0.6% chance of catching a wild Zapdos with a premier ball

**Note:**

This is for a Zapdos that would have a totally max HP stat at lv.50. If you give the HP of your Zapdos at lv.50, I can give you the precise percentage of the chances you had :)

Ok, now that I have your Zapdos' HP, the calculations are as followed:

(3×158-2×1)×0.4×1

———————————×1.5=

3×158

0.5974683..., rounded 0.6

As you can see the chance remains 0.6% :)