For a project, the number of days required by A to complete the task is 5 days longer than the number of days required by A and B in cooperation. The number of days required by B to complete the task alone is 20 days longer than the time required for A and B to complete the task. A and B cooperate to complete the task. How many days will the project take.
一项工程，甲做完成任务所需天数比甲、乙合作所需的天数多5天，乙独做完成任务所需天数比甲乙合作完成任务所需时间多20天，甲、乙合作完成这项工程需要多少天．
<result>10</result>