[tex]81-1\dfrac{1}{5}r < 55\qquad|\text{subtract 81 from both sides}\\\\-\dfrac{1\cdot5+1}{5}r < -26\qquad|\text{change the signs}\\\\\dfrac{6}{5}r > 26\qquad|\text{multiply both sides by 5}\\\\6r > 130\qquad|\text{divide both sides by 6}\\\\r > \dfrac{130}{6}\\\\r > \dfrac{65}{3}\to r > 21\dfrac{2}{3}[/tex]
