Skyhighbird.
As I said in my previous post, neither of the methods will get exactly the correct answer in the real question. But they will both get you an answer that will enable you to select the correct answer (because it will be the closest one to your answer).
Fark'n'ell.
I think that you will find that "the dickheads" have heard of sea breezes. That is why the real question specifies an inland airfiled at 1400.