20 yuan will be deducted from Qunar.com's money-saving task.

The reasons for this situation are platform service fee, task reward and membership fee.

1, platform service fee: As an online travel platform, Qunar.com needs to provide various services, such as hotel reservation, air ticket purchase and travel insurance. In order to maintain the operation of the platform and provide better services, Qunar.com will charge users a certain platform service fee. This is also one of the reasons for deducting 20 yuan from the deposit task.

2. Task reward: Qunar.com offers certain rewards to users by saving money, encouraging users to complete tasks and get more benefits and welfare. These tasks may include booking hotels, purchasing air tickets, etc. After completing the task, users can get certain rewards such as rebates or coupons. If the user fails to complete the assigned task or meet the requirements of the task, Qunar.com may deduct a certain fee as a punishment or reminder.

3, membership fee: Qunar.com's money-saving task also involves membership fees. If the user is a member of Qunar.com, he will enjoy certain membership privileges and benefits when completing the task. If members fail to renew their fees or complete their tasks on time, Qunar.com will deduct certain fees to maintain the stability of members' rights and interests and the continuity of services.