One week a librarian kept track of whether returned books were returned on time or not, and whether they had fewer than 200 pages or they had 200 pages or more. The results are shown in the table.
What is the probability that a randomly selected book returned that week was returned on time, given that it had 200 pages or more?



Returned on time
fewer than 200 pages—— 78
200 pages ir more ——116


Returned late
Fewer than 200 pages ——15
Returned late ——31