odd number on a fair die:
50%, as 1,3,5 are all odd and there are 6 sides on a die
tails: 50% as 2 sides.
But if you are asking together: for each possible side on the die, there is a possibility of heads or tails
1: H T
2: H T
3: H T
4: H T
5: H T
6: H T
so 12 possibilities.
to roll an odd number and have a coin land on tails
1: T
3: T
5: T
3 different possibilities satisfy that
so then the answer becomes: 3/12
so 25%
Hope This helps!