6 5/12 * (4 7/11 - 3 6/7) = 77/12 * (51/11 - 27/7) = 77/12 * (357/77 - 297/77) = 77/12 * 60/77 = 60/12 = 5
(40,425 + 4 3/8) : 2 4/5 = (40 17/40 + 35/8) : 14/5 = (1617/40 + 35/8) : 14/5 = (1617/40 + 175/40) : 14/5 = 1792/40 : 14/5 = 224/5 * 5/14 = 16
16 -- 100%
5 -- x%
x = 5*100/16 = 500/16 = 125/4 = 3125/100 = 31.25 %