"There are fifteen people" 或 "There are 15 people" 是表示有 15 名的正确用法。

这个表达的来源是英语的基本语法。在英语中,当数字用来表示数量时,通常不用序数形式(例如 first, second, third),而是用基数形式(例如 one, two, three)。

下面是几个例句:

There are fifteen people in the room. (房间里有 15 个人。)
There are 15 people in the group. (这个团体有 15 个人。)
I counted and there are 15 people here. (我数了一遍,这里有 15 个人。)