Possible Ratios of their ages 20 years ago:

1. 5:4
- If the present ages of the husband and wife are in the ratio 5:4, then 20 years ago, their ages could have been in the same ratio.
- Let's assume the present ages of the husband and wife are 5x and 4x respectively.
- Therefore, their ages 20 years ago would have been 5x-20 and 4x-20.
- The ratio of their ages 20 years ago would be (5x-20):(4x-20), which simplifies to 5:4.

2. 10:8
- If the present ages of the husband and wife were in the ratio 10:8, then 20 years ago, their ages would have been in the ratio 5:4.
- Let's assume the present ages of the husband and wife are 10x and 8x respectively.
- Therefore, their ages 20 years ago would have been 10x-20 and 8x-20.
- The ratio of their ages 20 years ago would be (10x-20):(8x-20), which simplifies to 5:4.

3. 15:12
- If the present ages of the husband and wife were in the ratio 15:12, then 20 years ago, their ages would have been in the ratio 5:4.
- Let's assume the present ages of the husband and wife are 15x and 12x respectively.
- Therefore, their ages 20 years ago would have been 15x-20 and 12x-20.
- The ratio of their ages 20 years ago would be (15x-20):(12x-20), which simplifies to 5:4.
Therefore, the possible ratios of their ages 20 years ago could be 5:4, 10:8, and 15:12.