According to themarking guidelines the answer includesit raining 0 days, however the question says "rains", I've been told from a credible source that there was something "shady" ( I think they meant that the markers marked those who included 0 days wrong) Anyone know anything?
the Li refers to the polylogarithim function which is not assessed at all in school level maths
Edit: or the logarithmic integral which is the integral of 1/log x