These numbers refer to the number of teeth on each of the three gears up front. So each of the three in a 48/38/28 set will be a little larger in diameter than the corresponding three in a 44/32/22 combo. To assess what the full outcome will be in terms of 'pedal rotations per MPH', you need to factor in the range of the rear cog set, tire diameter, etc. If all of these other factors are equal, the 44/32/22 would result in a lower ratio (more suited to say a mountain bike), while the 48/38/28 would probably be more typical of a hybrid or comfort (light off road / bike trail / casual) bike. Road bikes (designed for speed) might have the largest ring up in the 50's.

Don't get hung up on the stated order.