Ok, I'm still not totally convinced but I've already made the corresponding adjustments and passed the tests. Thanks for your comments!

"In the last basic test i get this error:

IN: 1000 2.0 50 1214 Year 1: 1070.0 Year 2: 1141.4 Year 3: 1214.228

3 should equal 4"

The instructions state the following: "the function nb_year should return n number of entire years needed to get a population greater or equal to p."
So even if I do not consider the decimals in the test I get the error, the result of year 3 already reaches the target quantity "p" that is received as a parameter. Where is the error?

I have the same error that @Xeferis mentions, when I click on the "Attempt" button I get the same message: "expected 3 to equal 4" but I don't understand why.

Great solution!