The reason why it cost an extra 15 yuan to buy a ticket for a friend may be due to the following factors:
Buying tickets late: If train tickets are not purchased at the beginning of the sale, the price may increase as the supply of tickets decreases. Friends may have purchased tickets when ticket supplies were tight or close to the departure time, so the ticket price was relatively high.
Priority ticket purchase service: Some ticket purchase platforms provide priority ticket purchase service, which requires additional payment. If a friend uses this type of service, the extra 15 yuan may be the cost of priority ticket purchase.
Additional charges for train tickets: The price of train tickets may include some additional charges, such as handling fees, delivery fees, etc. Friends may not notice these fees when purchasing tickets, causing the actual amount paid to be higher than expected.
Special Seats or Services: Train ticket prices may vary depending on seat type or service class. If your friend chooses more comfortable seats or services, the ticket price will naturally be higher.
Information asymmetry: Friends may not fully understand the fare information, resulting in not choosing the most favorable option when purchasing tickets.
In short, the reason why it cost an extra 15 yuan to buy a ticket for a friend may be caused by many factors. The specific situation needs to be analyzed based on the actual situation.