Let x = angle PRS, y = angle PQS.
Asked x-y = ?
1. Angle QPR = 30
Angle QPR = Angle QPS - Angle RPS
Angle RPS = 90-x
Angle QPS = 90-y
30 = QPR = (90-y) - (90-x) = x-y SUFF.
2. Angle PRQ + Angle PRQ = 150
Which is same as saying angle QPR = 30. (same as condition #1). SUFF too!
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