57,4:4+1 1/6:4 2/3 -(2,7+ 5 1/20)*0,8
-------------------------------------------------------
2 1/15 - (1 2/3 +1/5)

$frac{57,4 : 4+1 frac{1}{6}: 4 frac{2}{3}-(2,7+5 frac{1}{20}) *0,8 }{2 frac{1}{15}-(1 frac{2}{3} + frac{1}{5}) }$ =

$frac{14,35+ frac{7}{6}: frac{14}{3}-(2,7+ frac{101}{20} )*0,8 }{ frac{31}{15}- frac{5}{3}+ frac{1}{5} }$ =

$frac{14,35+ frac{1}{4}-(2,7+5,05)*0,8 }{ frac{31}{15}- frac{28}{15} }$ =

$frac{14,35+0,25-6,2}{ frac{1}{5} }$ = $frac{8,4}{0,2}$ =42