\(\dfrac{15\times7}{30\times11}=\dfrac{15\times7}{15\times2\times11}=\dfrac{7}{2\times11}=\dfrac{7}{22}\)
\(\dfrac{4\times5\times6}{12\times15\times9}=\dfrac{4\times5\times2\times3}{4\times3\times5\times3\times3\times3}=\dfrac{2}{3\times3\times3}=\dfrac{2}{27}\)
\(\dfrac{6\times8\times11}{33\times16}=\dfrac{3\times2\times8\times11}{3\times11\times8\times2}=1\)