Answer:
this can be solved by simple unitary method
[tex]time \: taken \: to \: remove \: \frac{5}{9} \: tons \: of \: dirt \: = 1 \: hr \\ time \: taken \: to \: remove \: \frac{31}{6} \: tons \: of \: dirt \: = \frac{31}{6} \times \frac{9}{5} \: hr \\ = \frac{93}{10}hr \\ = 9 \times \frac{3}{10} hr[/tex]