3/5 4/7; 8/15 11/20; сравните дроби! Срочно надо

3/5 = 21/354/7 = 20/3521/35 > 20/35  =>  3/5 > 4/78/15 = 32/6011/20 = 33/6033/60 > 32/60  =>  11/20 > 8/15