The first Corona virus outbreak was on 8th of december 2019

not on jan 9th 2020 as we were told

that means that we have 23 days from dec to virus to spread worldwide
and 31 days from jan 2020
54 days in total

considering the new incubation period of 4 days this means we have 54/4=13,5 cycles already
lets say 13:)

R0=4,1 now
each man infects 4,1 men per cycle

lets rose 4,1 to power 13 to asses honw many people are sick now

4,1^13=187.319.101 people worldwide
so we have 187 million infected people now

and the nubmer multiplies with 4 in 2 days