Which candle burns longer:a black one or a white one?

Which candle burns longer:a black one or a white one?
25.Why does a cook wear a high,white hat?
26.Can you name five days of the week without saying:Monday,Tuesday,Wednesday,Thursday,Friday?
27.What kind of dog never can bite and bark?
28.What has a soft bed but never sleeps,a big mouth but never speaks?