Just wow

thanks for your help.it solved

round off will solve the problem

Yes I think so , writing problem.

A problem with your code is not a kata issue, please read this: https://docs.codewars.com/training/troubleshooting/

You need to do that every year, not only at the end. If you only do that at the end, you'll get the wrong result. akar-0 already told you that:

You must round down for each year.

And that's what this shows:

At the end of the first year there will be: 
1000 + 1000 * 0.02 + 50 => 1070 inhabitants

At the end of the 2nd year there will be: 
1070 + 1070 * 0.02 + 50 => 1141 inhabitants (** number of inhabitants is an integer **)

At the end of the 3rd year there will be:
1141 + 1141 * 0.02 + 50 => 1213

It will need 3 entire years.

@Chrono79 I know there's no fractional population, but read again. Even if I rounded down 1214,22 to 1214, don't you agree that 1214 = 1214? And, in that test, 1214 is p. So if the idea was that p0 equals or surpasses p, 1214 (rounded down from 1214,22) would suffice.

Yes there's a problem with the kata's writing. I was wondering why I was getting that error. I have try to debug it but to no avail.

There is no fractional population, read the kata's description again.

You must round down for each year.

Test case saying the result is supposed to return 4 years is, in fact, 3 years. The input is (1000, 2, 50, 1214). If you do the math "by hand", in the third year you would have 1214,222 people. Even if you round down to 1214, 1214 is still equal to 1214. So, there's a problem with the kata's writing. It should say that the expected years is greater than 1214(p) instead of greater OR equal to... That or the expected result for this test should be 3 instead of 4.