Say I am EV Training in HP and I battle a Chansey while holding the Power Weight under the Virus of PokeRus. I know AFTER the battle I get 12 EVs in HP, but what if I use a HP Up after the battle, how many EVs is that? The basic question is this: How many EVs do I get when I use a HP Up?
All vitimins give 10 evs no matter what the situation (in this case pkrs) You can have a maxinum of 10 in each stat that will give you a 100evs or 25 stat points in hp.