What should be the base days for salary calculation?

Dear Sirs/Madam,
For example-
Case 1: If the monthly gross salary of an employee is Rs 30,000 and the employee joins an organization on 31st May, should his salary for May
(for one day of work) be Rs 30,000/31 (calendar day basis) or should it be Rs 30,000/30 or Rs 30,000/26 (on a fixed number of days
basis)?
Case 2: If the monthly gross salary of an employee is Rs 30,000 and the employee has loss of pay for 2 days in May, should the loss of pay value
be Rs (30,000/31) x 2 (calendar day basis) or should it be Rs (30,000/30) x 2 or Rs (30,000/26) x 2 (on a fixed number of days basis)?
Regards,
Amit

The best way is to consider month to consist of 30 days & do the calculation. If you do it by 26 days, the daily salary will be higher than what it will be that is calculated by dividing by 30 days. As such OT rate in the first case will be higher.
Whatever method you choose, apply it for both; payment & deduction.