Supplimentary angles add upto 180 degrees.
Given that angle P is three times angle Q-4 then ;
Let angle P be 3(x-4) = 3x -12
Let angle Q be x
Applying the rule of supplimentary angles;
Divide both sides by 4 to get value of x in degrees
x= 48 degrees
Angle Q = 48 degrees
Angle P = 3x-12 = (3*48)-12 = 132 degrees