Calculate total revenue share Suppose you have data such as this: January Total minutes of all videos watched: 50 Total minutes of video X watched: 25 Total revenue: 200 February Total minutes of all videos watched: 200 Total minutes of video X watched: 50 Total revenue: 500 Therefore for the two months taken together: Total minutes of all videos watch: 50 + 200 = 250 Total revenue: 200 + 500 = 700 I am confused about how to calculate the total amount earned by video X, if we assume that a video earns revenue based on the number of minutes it has been watched. Method 1: Total minutes of video X watched: 25 + 50 = 75 Revenue earned = 75 * 700 / 250 = 210 Method 2: January revenue = (25*200/50) = 100 February revenue = (50*500/200) = 125 Revenue earned = 100 + 125 = 225 Please help me wrap my head around how to think about this.

Your method two is correct.

In january, one half of the revenue was generated by video X, since half of the total watch time was spent looking at video X. This means that video X earned `100`, half of the total amount.

In february, the video earned one quarter of the total amount, meaning it earned `125`, making a total of `225`.

* * *

But why does the first method return different results? Well, in the first method, you make the mistake of making the january watch-time minutes equally valuable as the february ones. For example, in january, each minute watched generated a revenue of `4`, while in february, it only generated a revenue of `2.5`. Therefore, saying that the video X was watched for a total of `75` minutes is correct, but saying that each of those minutes was worth `700 / 250` is not. Some of those minutes were worth `200/50`, the others were worth `500/200`.