What does the slope 1/4 mean in context?

There is an increase of 1 million in revenue for every 4 units sold.

There is an increase of 4 million in revenue for every 1 unit sold

The slope of 1/4 means that for every unit increase in the independent variable (in this case, the number of units sold), there is a corresponding increase of 1/4 in the dependent variable (revenue). In other words, for every 4 units sold, there is an increase of 1 million in revenue.