Answer
The model is correct to one significant digit.
Work Step by Step
For 1940 (40 years after 1900,) t=40.
Inserting t=40 in the model obtined in part a,
$ P(40)=6.591\times\ln(40)-17.69\approx6.623,$
and when we compare it to $6.9$, only the first digits coincide.
The model is correct to one significant digit.
