Assuming they are saying they are hybrid
INT 1:7, it means basically that each 7 int points they add, they then add 1 str point. You can also build a hybrid by its balance, in this case, the balance of a hybrid int 7:1 is 87-88% mag balance, to achieve that simply take off all your equipment when you level and then put INT trying to get it to 88-87% mag balance (press C). Once you get 87-88% mag balance, then you add the rest (if there's any) of your points in STR. You might not be able to achieve such balances at the beginning, and there are some cases (if you are already at a certain lvl) where you'll not be able to achieve a balance at all unless it's through blues, but then it's another story.
Sort of more complicated now, you don't really need to know this: hybrid int 7:1 also means that every
8 points they have added, 1 is in str. Knowing that each lvl you receive 3 points to arrange as you please, at 90 cap, you have 267 points to be arranged (89 lvl ups from lvl 1), 267/
8 =~ 33 so
at lvl 90 a hybrid int 7:1 would have ~ 33 str points added, so 11 lvls of STR added. Hope I haven't complicated things too much.

lol, if you have any questions just ask.