Hi Sonia! We take the initial time of data measurement to start from end 2017 so that x = 0 at the end of 2017.

A growth rate of k% can be thought of as an “interest” rate of k%. This tags on to the “1” in the formula

Pfinal = P (1 + k%)^n.

Thank you so much! i understand it now :-)

I doubt addition of numbers to percentage is allowed in O levels. Might be marked down. Better to rewrite as k/100 first, then conclude k% is 11% and therefore k is 11

Sonia, for an alternative approach to this question you can refer to my comment in the main section