washington u.s. treasury secretary steven mnuchin say friday difficult trump administration tax plan cut tax wealthy earners cut tax hard create system go also cut tax top 10 percent mnuchin say institute international finance event washington sideline imf world bank semi-annual meet also say 10 percent invest lot money try create disproportionate tax cut top add mnuchin say still expect tax reform legislation reach president donald trump desk signature early december treasury 's mnuchin difficult cut tax top 10 percent