How many people have ever read that?

Imagine this were a question posed to a group of four applicants sitting in a room together. They have whiteboards, a computer… and of course the interviewer and question-poser, sitting there watching and listening to them address the challenge. As a group. And of course the interviewer will be happy to answer any questions and provide further guidance, if any of them ask.

Challenge: I want you to build a web application. There is a single text field, and a “Submit” button. A visitor can type or paste a passage of up to 100 words of English into the text field. When they click “Submit”, a model is used to estimate, as accurately as possible, how many people in the history of the world have ever read those exact words. Describe how you would approach this task.