how can u gain both strenght and muscle mass?

If you're getting bigger, you will be stronger. But I know that there are typically different workouts for if you are size training or strength training. I train for strength, not for size.

The two are intertwined somewhat. If you train for size, your strength is going to increase. If you train for strength, your size is going to increase a bit. The goal you train for is definitely going to show through more than the other though. I train for strength in order to punch and kick harder.

Here's something I've found during my research...

01-05 reps = Strength/Power
06-12 reps = Hypertrophy (size) & some strength
12-20 reps = Local endurance/little size

Those rep ranges are what I follow also.

Yeah, those rep ranges I've seen before too...good rule of thumb.

and if you're going for a few goals, or all 3, vary your rep count for each set. eg 12 10 8 6.. somthin like that

and remember most of those numbers mean ~12 then failure ~10 then failure (so you've really got to know your body well to anticipate reps)

do you maen per set?

i usually try to do 3x10 or failure.

just try to mix things up after awhile to keep things fresh and add variety

i do the pyramid workout, all sets to failure

1x15
1x10
1x6
1x3

thats just a rough example, but i put enough weight to get failure at about the given rep. 30sec - 1min rest between each set.