Calculus help for viruses

Question

The center for disease control has found that a virus is spreading at a rate of $4.3$% per year. That is $\frac {dV}{dt}=.043V$. If there are currently $12,000$ people infected by the virus, how long will it take to have 50,000 people infected? How do I start this problem?

Answer 1

Hint : $\frac {dV}{V}=0.43dt$ then integrate with appropriate limits where V varies from $12,000$ to $50,000$ and time varies from $0$ to $t$

that is $$\int_{12000}^{50000} \frac {dV}{V}= \int_0^t 0.043dt$$