Help ! <mpr> (in General)

if i spend about 7mil cb2 to buy last minion. How much mpr pump i 'd be looking at ?
75k-->100k?

From wiki:

Enlisting another Minion

When enlisting another minion you get the choice between 2 prices (except when you have a base character)

* Choosing the top option, the most expensive one, the new minion will get 1 experience for every $3 you pay.
* Choosing the bottom option, the less expensive one, the new minion will get 1 experience for every $5 you pay.

however i have no idea how much mpr your character would gain... could be 75k, could be more, could be less

the exp / mpr ratio is what i interest to know

By my best guess your looking at about 60k MPR.

Take note of your exact current MPR, then train a small amount of XP. Check how much MPR you've gained and divide this into the amount of XP you trained. This will give you your current XP/MPR ratio. Keep in mind that this ratio rises as your MPR rises.
Now assuming you opt for the more expensive minion, divide the cost of the new minion by 3 to find out how much XP the minion will have. Then divide the amount of XP by your current XP/MPR ratio to find out how much MPR you'll gain. Remember that the XP/MPR ratio will rise a bit as you train the new XP.
My guess is that you'd gain about 45k MPR from a 7M minion at your current MPR.