Find the measure of x. Line PU has points R and S between points P and U, lines QR and ST are parallel, line QR intersects line PU at point R, line ST intersects line PU at point S, the measure of angle PRQ is 150, and the measure of angle UST is 15 ( x plus 1 ).

x = 1
x = 9
x = 10
x = 11