Bonsoir,
A)
7, 14
2/20 = 1/10
B)
2,4,6,8,10,12,14,16,18,20
10/20 = 1/2
c)
impossible
D)
20/20 = 1/1
E)
1,3,5,7,9,11,13,15,17,19
F)
3/20