Since PQR forms a straight angle, then x∘+y∘+x∘+y∘+x∘=180∘ which gives 3x+2y=180.
Since x+y=76 and 2x+2y+x=180, then 2(76)+x=180 or x=180−152=28.
Want a route through all this instead of an archive? The track
puts 2,444 problems in a working order, from Junior Challenge level to the IMO shortlist.