oiee Nas(ey), tero jagir khatrama xa hai keta. :)

foreach (var car in InComing)
{
numOfCars += car;
}
--------------------------------

analysis as according to your soln:

int[] incoming = { 10, 0, 0, 4, 20 };

numOfCars = 34;

numOfCars/countPerDay = Math.Ceiling will give you 5

but actual answer should be 6.
:)
plz redo it without dreaming about priyanka  and re-post it.