1) 2/5 : 1/3 = (2/5 * 15) : (1/3 * 15) = 30/5 : 15/3 = 6 : 5
2) 4/7 : 1/2 = (4/7 * 14) : (1/2 * 14) = 56/7 : 14/2 = 8 : 7
3) 5/6 : 3/8 = 5/6 * 8/3 = (5*4)/(3*3) = 20/9 = 20 : 9
4) 3 1/9 : 2 1/6 = 28/9 : 13/6 = 28/9 * 6/13 = (28*2)/(3*13) = 56/39 = 56 : 39
5) 1 5/12 : 2/15 = 17/12 * 15/2 = (17*5)/(4*2) = 85/8 = 85 : 8
6) 1/8 : 1 7/12 = 1/8 : 19/12 = 1/8 * 12/19 = (1*3)/(2*19) = 3/38 = 3 : 38