Answer:
b) 42°
Explanation:
When two triangles share the same base (in this case, side QR), one angle is half of the other one. In this case:
1/2*∠QPR = ∠QSR
From the picture,
∠QSR = 21°
Replacing into the equation and solving for ∠QPR:
∠QPR = 2*21° = 42°