1. Suppose you are trying to decide whether to drive or take the train to Busan to attend a concert. You have ample cash to do either, but you don't want to waste money needlessly. Is the cost of the train ticket relevant in this decision? In other words, should the cost of the train ticket affect the decision of whether you drive or take the train to Busan? Is the cost of the train ticket is relevant or the cost of the train ticket is not relevant?
2. Suppose you are trying to decide whether to drive or take the train to Busan to attend a concert. You have ample cash to do either, but you don't want to waste money needlessly. Is the annual cost of licensing your car relevant in this decision? Is the cost of the licensing is relevant or the cost of the licensing is not relevant?
3. Suppose that your car could be sold now for 5,000. Is this a sunk cost? Is it a sunk cost or it is not a sunk cost?