Vaccine Drive

Suppose the population is divided into the age groups $[1, 10], [11, 20], [21, 30], \ldots, [91, \infty)$. The age groups are numbered from $1$ to $10$ and there are $X_i$ people in age group $i$. The COVID vaccine drive has started and people will be vaccinated in the decreasing order of their age groups. Suppose $P$ people are vaccinated per day and if less than $P$ people are left in an age