\(a,\dfrac{x}{15}=2\dfrac{2}{3}=\dfrac{8}{3}\Rightarrow x=\dfrac{15\cdot8}{3}=40\\ b,\dfrac{108}{x}=1\dfrac{4}{5}=\dfrac{9}{5}\Rightarrow x=\dfrac{108\cdot5}{9}=60\\ c,\dfrac{x}{2}< 1\dfrac{1}{2}\Rightarrow\dfrac{x}{2}=\dfrac{3}{2}\Rightarrow x< 3\)
\(\dfrac{x}{15}=2\dfrac{2}{3}\)
\(\dfrac{x}{15}=\dfrac{8}{3}\)
\(\dfrac{x}{15}=\dfrac{40}{15}\)
\(\Rightarrow x=40\)