The bacterial population $P$ in a culture grows according to a quadratic model $P(t)=a{t}^2+bt+c$, where $t$ is the time in hours and $P(t)$ is the population in thousands. At the start of the observation ($t=0$), the population is 10 thousand. After 1 hour, the population is 12 thousand. After 3 hours, the population is 30 thousand. What is the bacterial population, in thousands, after 5 hours?