A: Yes they are similar, as the angles are the same (If you know two angles a and b of a triangle, you automatically know the third c=180*-a-b because the three angles have to sum up to 180*)
The scale factor is 1.5 which can be calculated by dividing corresponding side lengths (e.g. 9/6=1.5)
B Yes they are similar, as the corresponding angles are equal and the sidelengths habe been increased by factor 2.5 (=7.5/3)