this is not necessary: n >= 5 &&

Why is there 7?

You cannot round 1000/36 to 27.7778, because it's not accurate.

what if you take a number which digits' sum is not divisible by 9? E.g. 5631?

readable :)

too clever :D

i didnt really get it :(

could you explain this solution pls?

clever, but hard to understand.

thanks for the reply :)

lol

What kind of magic is this?

Nice :)

We've learnt that the average should always be a double.
What is the s1 would be 59.9999999, I think it should be considered as 60, and hence it's a different grade.