I assume that these are traditional IRAs, not Roth IRAs.
If your father died after his RBD, your annual RMDs under the 10-year rule are based on your life expectancy from the Single Life Expectancy table based on your age attained in 2024 reduced by 1 each subsequent year. As other's have said, the table is in IRS Pub 590-B.
The penalty for not taking the RMD in 2024 has been waived, so you don't have to take the 2024 RMD (if subject to RMDs), but you might still want to take more than the RMD each year to avoid a large distribution required to completely deplete the account in year 10.
With both inherited IRAs coming from the same decedent and subject to the same RMD requirements, the total RMD for each year can be satisfied with distributions from either account in any combination.
