If you have LOTS of classes, you might end up 3.9 something.
Say she did 5 classes a semester, so 10 a year. 9 were A's and 1 a B, so over four years, you would have 36 A's and 4 B's. 36x4= 144, 3x4=12. 144+12=156 156 divided by 40 = 3.9
7 classes a semester= 14 a year. 52 A's and 4B's = 220 divided by 56 = 3.92857......
Even the above 7 classes a semester with only one B for the whole four years comes out to 3.98214......
The more A classes, the more 'diluted' those B's become, but you still can't get to 4.0. HOWEVER - if you have honors classes that get counted on a scale of an A is 5 points on a 4 point scale, then you CAN get a 4.0. ONE 5 point A each time you get a 3 point B means you just got 8 points for those two classes, the same as if you got two A's. OR if all the B's were honors classes, they would count 4 points, as if they were an A.
clear as mud?