Ok, in first place:
1. Two triangles are similar if they have two equal angles (AA).
2. Two triangles are similar if they have proportional sides (SSS).
3. Two triangles are similar if they have two proportional sides and the angle between them is equal (SAS).
The first pair of triangles are similar because they have proportional sides. As you can see from the first picture:
2DE=PQ ; 2EF=QR ; E=Q
2*2=4 ; 2*3=6 ; 50=50
About the second pair of triangles we are not able conclude anything since they only provide two angles and one of them is different to the other