Xiaodong plays table tennis with his parents. It takes 5 minutes for every two players to play one game. If each player plays two games, how many minutes will it take at least?
小东和爸爸妈妈打乒乓球，每两人打一局要5分钟，若每人打两局，至少要多少分钟．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<result>15</result>