2,5x : 4 2/3= 1/21:10
2,5х / 4 2/3 = 1/21 /10 2,5х / 14/3 = 1/210 2,5х = 1/210 * 14/3 2,5х = 1/45 112,5х = 1 х = 1/112,5 х = 2/225