Extra ones cost about $150 each.

VOA: standard.2010.03.11

I think these extra pictures sometimes they're helpful, sometimes they just make the book cost a lot more.

我想这些补充的图片有时是有用的,有时仅仅是把书价抬高了一点

耶鲁公开课 - 基础物理课程节选

At the margin, I'm reaping, I'm bearing the cost for the extra unit of effort I contribute, but I'm only reaping half of the induced profits of the firm, because of profit sharing.

从边际角度分析,我承担了多付出的全部边际成本,但我却只能得到一半的边际收益,因为利润是均分的

耶鲁公开课 - 博弈论课程节选