From the NY Times:
“The Interview” generated roughly $15 million in online sales and rentals during its first four days of availability, Sony Pictures said on Sunday.
Sony did not say how much of that total represented $6 digital rentals versus $15 sales. The studio said there were about two million transactions over all.
Sony didn’t say, but the math is clear. Solve for X (number of digital rentals):
(6 * x) + (15 * (2,000,000 – x)) = 15,000,000
Not sure why the NY Times can’t do math, that would be about 1,666,667 rentals and 333,333 sales.