Supplementary angles are those angles that sum up to 180 degrees Calculations: Let the angles are ∠A and ∠B ∠A−∠B=20∘ ∠A+∠B=180∘ Adding both equation we get 2∠A=200∘ ∠A=100∘ ∴∠B=80∘ Now, According to the Question statement p is the smallest angle ∴∠B=80∘ ∴3p−50∘=3×80∘−50∘=240∘−50∘=190∘