Here in the question, it is asked how many Eyes We have so that means here the person who has asked the question is also including the person who is suppose to give the answer. In a clear understanding, the Conversation is happening between 2 people 1st who asked the question and 2nd to whom it has been asked, which means there are 4 eyes.
There are three boxes in a table. One of the box contains Gold and the other two are empty. A printed message contains in each box. One of the message is true and the other two are lies. The first box says 'The Gold is not here'. The Second box says 'The Gold is not here'. The Third box says 'The Gold is in the Second box'. Which box has the Gold?
As the message contains one truth, the third says that the gold is in the second box, if it is to be true, then the first box message will also become true. So Gold cannot be in second and third boxes. Gold is in the first box.
It is Charcoal which is black when we buy it or when not being used. It gets red in appearance when put in use means to say when burning. And eventually when it's been consumed by fire or after getting burned out or used up, changes into ashes which look grey in color.